CN105198143A - High-concentration wastewater zero-discharging method - Google Patents
High-concentration wastewater zero-discharging method Download PDFInfo
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- CN105198143A CN105198143A CN201410273247.0A CN201410273247A CN105198143A CN 105198143 A CN105198143 A CN 105198143A CN 201410273247 A CN201410273247 A CN 201410273247A CN 105198143 A CN105198143 A CN 105198143A
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/33—Wastewater or sewage treatment systems using renewable energies using wind energy
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- Separation Using Semi-Permeable Membranes (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
Abstract
The invention relates to the field of industrial wastewater treatment, in particular to a high-concentration wastewater zero-discharging method. Accoridng to the method, a 'nanofiltration + efficient reverse osmosis + membrane distillation + evaporative crystallization' method is adopted to treat high-concentration wastewater. Firstly, nanofiltration is adopted to remove hardness, multivalent ions and parts of organic matter in the high-concentration wastewater so as to obtain nanofiltration producing water and nanofiltration concentrated water, then an efficient reverse osmosis technology is adopted to conduct deep concentration treatment on the nanofiltration producing water, deep concentration treatment is conducted on the obtained efficient reverse osmosis concentrated water through membrane distillation to obtain membrane-distillation concentrated water, further evaporative crystallization treatment is performed to enable salt solids in the membrane-distillation concentrated water to crystallize out, and centralized drying disposal is performed, wherein salt is added into the nanofiltration concentrated water to perform precipitation treatment so as to obtain calcium residues, supernate obtained after precipitation is subjected to activated carbon adsorption and then is mixed with the high-concentration wastewater, and the mixed liquid is fed into a nanofiltration unit for circular treatment. By means of the high-concentration wastewater zero-discharging method, water resources are recycled to the most degree while the problem of high-concentration wastewater discharging is solved, and zero discharging of high-concentration wastewater is basically achieved.
Description
Technical Field
The invention relates to the field of industrial wastewater treatment, in particular to a zero discharge method of high-concentration wastewater. In particular to a zero discharge method for treating high-concentration wastewater by utilizing a membrane separation technology, and more particularly relates to a zero discharge method for treating high-concentration wastewater by 'nano-filtration, high-efficiency reverse osmosis, membrane distillation and evaporative crystallization'.
Background
In recent years, high-concentration wastewater generated by petrochemical enterprises is a difficult treatment problem, and the high-concentration wastewater can not be discharged or recycled, so that great trouble is brought to various enterprises. Therefore, a new separation technology is needed to solve the problem of treating and discharging the high-concentration wastewater.
Nanofiltration (NF) is a membrane separation technology between ultrafiltration and reverse osmosis, with a pore size of several nanometers and a cut-off molecular weight of 200-1000. Nanofiltration has the following characteristics: organic matters and multivalent ions with molecular weight more than 100 can be intercepted, and small-molecular organic matters and monovalent ions are allowed to permeate; the device can operate under severe conditions of high temperature, acid, alkali and the like, and is pollution-resistant; the operation pressure is low, the membrane flux is high, and the operation cost of the device is low; the ion exchange membrane has a south-of-the-road effect on anions with different valence states, and the charge property, the ionic valence number and the concentration of the material have great influence on the separation efficiency of the nanofiltration membrane. Compared with ultrafiltration or reverse osmosis, the nanofiltration process has poor interception on monovalent ions and organic matters with the molecular weight of less than 200, and has higher removal rate on bivalent or multivalent ions and organic matters with the molecular weight of 200-500. Based on the characteristics, the nanofiltration process is mainly applied to water softening and purification, separation, classification and concentration of substances with the relative molecular mass of hundreds, decolorization, deodorization and the like. In the actual wastewater treatment, nanofiltration and other wastewater treatment processes can be combined to further reduce the cost and improve the treatment effect.
The High Efficiency Reverse Osmosis (HERO) technology was a new technology developed in the last 90 th century, combining the advantages of both ion exchange and reverse osmosis, being the most advanced reverse osmosis technology at present. The core process principle is as follows: removing hardness in the water by adopting ion exchange, and removing salt by reverse osmosis; meanwhile, reverse osmosis operates under the condition of high pH, and silicon mainly exists in an ion form, so that the reverse osmosis membrane is not polluted and can be removed through reverse osmosis; organic matters in water can be saponified or weakly ionized under the condition of high pH, organic matters and biological pollution of the reverse osmosis membrane can not be caused, a large amount of acid and alkali are saved, and the recovery rate of the high-efficiency reverse osmosis system is improved. The reverse osmosis concentrate can be further concentrated to a higher level using a high efficiency reverse osmosis technique, however, this technique is premised on first removing hardness from the wastewater to a very low level so that the reverse osmosis concentrate system operates at a high pH.
Although the high-efficiency reverse osmosis technology can further concentrate high-salinity and high-hardness wastewater such as reverse osmosis concentrated water to higher concentration, a small amount of more concentrated high-salinity concentrated water is discharged. Membrane Distillation (MD) is a membrane technology that has the highest desalination efficiency so far, and has a desalination rate as high as 99% or more, and is gradually receiving attention from experts of various countries and has been widely studied because of its ability to remove salts at higher concentrations and higher desalination rates. The membrane distillation is a novel membrane separation process which adopts a microporous hydrophobic membrane and takes the steam pressure difference at two sides of the membrane as a driving force. The membrane used for membrane distillation is a hydrophobic microporous membrane which is not wetted by the solution to be treated, i.e. only steam can enter the membrane pores, and liquid cannot penetrate the membrane pores. The advantages of membrane distillation are mainly: the produced water has good quality, high desalination rate and high water recovery rate, and can utilize industrial waste heat. Compared with multi-effect evaporation, the membrane distillation can be operated at low temperature, the produced water quality is better, the distillation efficiency is higher, the scaling and corrosion problems of an evaporation tower do not exist, and the equipment cost is lower than that of a conventional distillation tower; compared with reverse osmosis, the membrane distillation can be operated at normal pressure, has low requirements on pretreatment, can treat high-salinity wastewater which cannot be treated by reverse osmosis, and has higher water recovery rate.
Chinese patent CN102557321A relates to a zero discharge method of high-concentration wastewater, and realizes zero discharge of the high-concentration wastewater by adopting a crystallization technology, a membrane distillation technology, a microwave catalytic combustion technology and a solar and wind power generation technology. In the patent, the high-concentration wastewater firstly enters a crystallization device to crystallize inorganic substances, then is separated by a membrane distillation device, water vapor penetrating through a membrane distillation membrane is cooled to obtain pure water, other mixed steam not penetrating through the membrane distillation membrane is condensed to obtain miscellaneous water, and non-condensable gas in the mixed steam enters a subsequent microwave catalytic combustor to be decomposed to obtain non-toxic and harmless micromolecular substances. Although the patent also relates to a zero-discharge method of high-concentration wastewater, the zero-discharge process flow of the patent cannot optimize each process, and the zero-discharge process flow in the application fully integrates the advantages of each technology and is completely different from the process flow in the patent.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method for zero discharge of high-concentration wastewater, and aims to provide a method for treating the high-concentration wastewater by adopting nanofiltration, high-efficiency reverse osmosis, membrane distillation and evaporative crystallization. The method comprises the steps of firstly removing multivalent ions such as hardness and partial organic matters in high-concentration wastewater by nanofiltration to obtain nanofiltration product water and nanofiltration concentrated water, then carrying out deep concentration treatment on the nanofiltration product water by adopting a high-efficiency reverse osmosis technology to obtain high-efficiency reverse osmosis product water and high-efficiency reverse osmosis concentrated water, carrying out deep concentration treatment on the high-efficiency reverse osmosis concentrated water by membrane distillation to obtain membrane distillation product water and membrane distillation concentrated water, carrying out evaporative crystallization treatment on the membrane distillation concentrated water, crystallizing salts in the membrane distillation concentrated water, and carrying out concentrated drying treatment. The nanofiltration concentrated water generated in the treatment process is added with salt for precipitation treatment to obtain calcium slag, the supernatant after precipitation is subjected to activated carbon adsorption, and the adsorbed produced water and high-concentration wastewater are mixed and enter a nanofiltration unit for circular treatment. The high-efficiency reverse osmosis produced water, membrane distillation produced water and evaporation crystallization produced water produced in the treatment process can be recycled for the production process. The method for treating the high-concentration wastewater solves the problem of discharge of the high-concentration wastewater, simultaneously recycles water resources to the maximum extent, and basically realizes zero discharge of the high-concentration wastewater.
In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:
the zero discharge method of the high-concentration wastewater is characterized by comprising the following steps:
(1) and (4) nanofiltration: the high-concentration wastewater enters a nanofiltration unit for nanofiltration filtration treatment, multivalent ions such as hardness and the like and part of organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters a sedimentation tank for treatment in the step (2), salts are added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is subjected to centralized drying treatment, supernatant in the sedimentation tank enters an activated carbon adsorption unit for activated carbon adsorption, and then the adsorbed produced water returns to the nanofiltration unit and is mixed with the high-concentration wastewater to enter the nanofiltration unit for circulation treatment;
(2) efficient reverse osmosis: the nanofiltration produced water is subjected to alkali adjustment treatment, and then enters a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
(3) membrane distillation: carrying out acid regulation treatment on the high-efficiency reverse osmosis concentrated water, and then, carrying out deep concentration treatment on the high-efficiency reverse osmosis concentrated water in a membrane distillation unit to obtain membrane distillation produced water and membrane distillation concentrated water;
(4) evaporation and crystallization: and (4) the membrane distillation concentrated water enters an evaporation crystallization unit for evaporation crystallization treatment to obtain salt crystals and evaporation crystallization water.
On the basis of the technical scheme, the high-efficiency reverse osmosis water production, the membrane distillation water production and the evaporative crystallization water production can be recycled for the production process.
On the basis of the technical scheme, the main water quality characteristics of the high-concentration wastewater are as follows: pH 7-9, conductivity 10000-20000 mu s/cm, CODcr100～500mg/L，Na+2000～4000mg/L，Cl-2500-5000 mg/L, total hardness (CaCO)3) 1500-3000 mg/L and 50-100 mg/L of silicon solution.
On the basis of the technical scheme, in the nanofiltration unit in the step (1), the nanofiltration membrane component adopts a roll-type membrane component, and the nanofiltration membrane material is polyamide or sulfonated polyether sulfone.
On the basis of the technical scheme, the operating conditions of the nanofiltration unit in the step (1) are as follows: the operating pressure of the feed liquid side is 0.5-1 MPa.
On the basis of the technical scheme, the salt in the step (1) is sodium sulfate or sodium carbonate or a mixture of the sodium sulfate and the sodium carbonate, and the adding amount of the salt needs to meet the following requirements: ca2+: the molar ratio of the salts is 1: 1.
on the basis of the technical scheme, the activated carbon in the step (1) is powdered activated carbon or granular activated carbon, and the adding amount of the activated carbon needs to meet the following requirements: activated carbon: the mass ratio of COD is 2: 1-10: 1, the activated carbon after saturated adsorption can be directly used as fuel for combustion treatment.
On the basis of the technical scheme, the high-concentration wastewater is treated by the nanofiltration unit, and the water recovery rate is higher than 92%.
On the basis of the technical scheme, the alkali adjustment treatment in the step (2) is to adjust the pH value of nanofiltration water to 9-11 by using sodium hydroxide.
On the basis of the technical scheme, the operating conditions of the high-efficiency reverse osmosis unit in the step (2) are as follows: the pH of the wastewater on the feed liquid side is 9-11, and the operating pressure on the feed liquid side is 2-5 MPa.
On the basis of the technical scheme, in the high-efficiency reverse osmosis unit in the step (2), the membrane component of the high-efficiency reverse osmosis is in a roll-type membrane component, and the membrane material is polyamide; the high-efficiency reverse osmosis components are in one group, or a plurality of groups are connected in series, or a plurality of groups are connected in parallel.
On the basis of the technical scheme, the nanofiltration water produced by the alkali adjustment treatment is treated by a high-efficiency reverse osmosis unit, and the water recovery rate is higher than 75%.
On the basis of the technical scheme, the acid adjusting treatment in the step (3) is to adjust the pH value of the high-efficiency reverse osmosis concentrated water to 7-9 by using hydrochloric acid.
On the basis of the technical scheme, the operation conditions of the membrane distillation unit in the step (3) are as follows: the pH value of the wastewater on the feed liquid side is 7-9, the temperature of the wastewater on the feed liquid side is 65-85 ℃, the membrane surface flow rate on the feed liquid side is 0.6-1.2 m/s, and the vacuum degree on the permeate side is-0.075-0.095 MPa.
On the basis of the technical scheme, in the membrane distillation unit in the step (3), the membrane material of the membrane distillation assembly is polyvinylidene fluoride, polytetrafluoroethylene or polypropylene; the pore diameter of the membrane is 0.15-0.2 μm.
On the basis of the technical scheme, the membrane distillation component is in a hollow fiber type or plate type.
On the basis of the technical scheme, the membrane distillation mode is internal pressure type vacuum membrane distillation; the membrane distillation components are in one group, or a plurality of groups are connected in series, or a plurality of groups are connected in parallel.
On the basis of the technical scheme, the high-efficiency reverse osmosis concentrated water subjected to the acid adjusting treatment is treated by the membrane distillation unit, and the water recovery rate is higher than 75%.
On the basis of the technical scheme, the evaporative crystallization unit in the step (4) adopts the existing commercial evaporative crystallizer, and the heat source adopts waste steam heating or electric heating.
On the basis of the technical scheme, the membrane distillation concentrated water is treated by an evaporation crystallization unit, and the water recovery rate is higher than 80%.
The substantial difference between the present invention and the prior art is: aiming at the problem of difficult treatment of high-concentration wastewater in the prior art, a method of nanofiltration, high-efficiency reverse osmosis, membrane distillation and evaporative crystallization is adopted for treatment. Firstly, removing multivalent ions such as hardness and partial organic matters in wastewater by nanofiltration, then carrying out deep concentration treatment on nanofiltration produced water by adopting a high-efficiency reverse osmosis technology to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water, carrying out membrane distillation deep concentration treatment on the high-efficiency reverse osmosis concentrated water to obtain membrane distillation produced water and membrane distillation concentrated water, carrying out evaporation crystallization treatment on the membrane distillation concentrated water, crystallizing salts in the membrane distillation concentrated water, and carrying out concentrated drying treatment. The high-efficiency reverse osmosis produced water, membrane distillation produced water and evaporation crystallization produced water produced in the treatment process can be recycled for the production process. Through the process flow, the difficult problem of the discharge of the high-concentration wastewater is solved, the water resource is recovered to the maximum extent, and the zero discharge of the high-concentration wastewater is basically realized. Compared with the prior art, the method and the device make full use of the technical advantages of various treatment processes, and the treatment process is more reasonable and feasible.
The zero discharge method of the high-concentration wastewater has the beneficial effects that:
1. aiming at high-concentration wastewater, on the basis of removing hardness and other multivalent ions and partial organic matters in the high-concentration wastewater by nanofiltration, the high-efficiency reverse osmosis technology is used for coupling the membrane distillation technology and the evaporative crystallization technology for deep concentration treatment, so that water resources are recovered to the maximum extent, and the problem of deep treatment and even zero emission of the high-concentration wastewater is solved;
2. the method fully utilizes the advantages of removing multivalent ions such as hardness and part of organic matters by nanofiltration, removes the hardness and part of organic matters in the high-concentration wastewater, and is convenient for subsequent high-efficiency reverse osmosis treatment;
3. the nanofiltration process effectively reduces membrane pollution in the subsequent high-efficiency reverse osmosis process, and improves the recovery rate of a high-efficiency reverse osmosis system;
4. compared with the conventional reverse osmosis, the efficient reverse osmosis technology adopted by the invention effectively slows down membrane pollution by adjusting the pH of the inlet water, and prolongs the cleaning period and the service life of the reverse osmosis membrane;
5. the membrane distillation process in the invention does not need external pressure or has small external pressure, and the method is simple and easy to operate;
6. the membrane pollution in the membrane distillation process is light, and the continuous and stable running time of the process is prolonged;
7. by adopting the method, a large amount of produced water meeting the recycling requirement can be obtained, the problem of difficult treatment of high-concentration wastewater is solved, zero emission is basically realized while the water resource is recovered to the maximum extent, and the method has important environmental benefit and social benefit;
8. the method effectively integrates the technical advantages of various treatment processes, and optimizes the process flow of advanced treatment and recycling of high-concentration wastewater. Compared with the method for directly carrying out multi-effect evaporation or membrane distillation on the wastewater, the method has low operation cost and effectively reduces scaling and organic pollution;
the conductivity of the produced water of the whole system of the high-concentration wastewater treated by the method is less than or equal to 300 mu S/cm, and the COD of the produced watercr<10mg/L, and the water recovery rate of the whole system is higher than 93 percent.
Drawings
The invention has the following drawings:
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the method for zero discharge of high concentration wastewater of the present invention specifically comprises the following steps:
(1) and (4) nanofiltration: the high-concentration wastewater enters a nanofiltration unit for nanofiltration filtration treatment, multivalent ions such as hardness and the like and part of organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters a sedimentation tank for treatment in the step (2), salts are added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is subjected to centralized drying treatment, supernatant in the sedimentation tank enters an activated carbon adsorption unit for activated carbon adsorption, and then the adsorbed produced water returns to the nanofiltration unit and is mixed with the high-concentration wastewater to enter the nanofiltration unit for circulation treatment;
(2) efficient reverse osmosis: the nanofiltration produced water is subjected to alkali adjustment treatment, and then enters a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
(3) membrane distillation: carrying out acid regulation treatment on the high-efficiency reverse osmosis concentrated water, and then, carrying out deep concentration treatment on the high-efficiency reverse osmosis concentrated water in a membrane distillation unit to obtain membrane distillation produced water and membrane distillation concentrated water;
(4) evaporation and crystallization: the membrane distillation concentrated water enters an evaporation crystallization unit for evaporation crystallization treatment to obtain salt crystals and evaporation crystallization water;
wherein, the high-efficiency reverse osmosis water production, the membrane distillation water production and the evaporative crystallization water production can be reused in the production process.
On the basis of the scheme, the main water quality characteristics of the high-concentration wastewater are as follows: pH 7-9, conductivity 10000-20000 mu s/cm, CODcr100～500mg/L，Na+2000～4000mg/L，Cl-2500-5000 mg/L, total hardness (CaCO)3) 1500-3000 mg/L and 50-100 mg/L of silicon solution.
On the basis of the scheme, in the nanofiltration unit in the step (1), the nanofiltration membrane component adopts a roll-type membrane component, and the nanofiltration membrane material is polyamide or sulfonated polyether sulfone.
On the basis of the scheme, the operating conditions of the nanofiltration unit in the step (1) are as follows: the operating pressure of the feed liquid side is 0.5-1 MPa.
On the basis of the scheme, the salt in the step (1) is sodium sulfate or sodium carbonate or a mixture of the sodium sulfate and the sodium carbonate (the mixture in any proportion), and the adding amount of the salt needs to meet the following requirements: ca2+: the molar ratio of the salts is 1: 1.
on the basis of the scheme, the activated carbon in the step (1) is powdered activated carbon or granular activated carbon, and the adding amount of the activated carbon needs to meet the following requirements: activated carbon: the mass ratio of COD is 2: 1-10: 1, the activated carbon after saturated adsorption can be directly used as fuel for combustion treatment.
On the basis of the scheme, the high-concentration wastewater is treated by the nanofiltration unit, and the water recovery rate is higher than 92%.
On the basis of the scheme, the alkali adjustment treatment in the step (2) is to adjust the pH value of nanofiltration water to 9-11 by using sodium hydroxide.
On the basis of the scheme, the operating conditions of the high-efficiency reverse osmosis unit in the step (2) are as follows: the pH of the wastewater on the feed liquid side is 9-11, and the operating pressure on the feed liquid side is 2-5 MPa.
On the basis of the scheme, in the high-efficiency reverse osmosis unit in the step (2), the membrane module of the high-efficiency reverse osmosis is a spiral-wound membrane module, and the membrane material is polyamide;
the high-efficiency reverse osmosis components are in one group, or a plurality of groups are connected in series, or a plurality of groups are connected in parallel.
On the basis of the scheme, the nanofiltration water produced by the alkali adjustment treatment is treated by a high-efficiency reverse osmosis unit, and the water recovery rate is higher than 75%.
On the basis of the scheme, the acid adjusting treatment in the step (3) is to adjust the pH value of the high-efficiency reverse osmosis concentrated water to 7-9 by using hydrochloric acid.
On the basis of the scheme, the operation conditions of the membrane distillation unit in the step (3) are as follows: the pH value of the wastewater on the feed liquid side is 7-9, the temperature of the wastewater on the feed liquid side is 65-85 ℃, the membrane surface flow rate on the feed liquid side is 0.6-1.2 m/s, and the vacuum degree on the permeate side is-0.075-0.095 MPa.
On the basis of the scheme, in the membrane distillation unit in the step (3), the membrane material of the membrane distillation assembly is polyvinylidene fluoride, polytetrafluoroethylene or polypropylene; the pore diameter of the membrane is 0.15-0.2 μm.
On the basis of the scheme, the membrane distillation module is in a hollow fiber type or a plate type.
On the basis of the scheme, the membrane distillation form is internal pressure type vacuum membrane distillation; the membrane distillation components are in one group, or a plurality of groups are connected in series, or a plurality of groups are connected in parallel.
On the basis of the scheme, the high-efficiency reverse osmosis concentrated water subjected to the acid adjusting treatment is treated by a membrane distillation unit, and the water recovery rate is higher than 75%.
On the basis of the scheme, the evaporative crystallization unit in the step (4) adopts the existing commercial evaporative crystallizer, and the heat source adopts waste steam heating or electric heating.
On the basis of the scheme, the membrane distillation concentrated water is treated by an evaporation crystallization unit, and the water recovery rate is higher than 80%.
Several specific examples follow.
Example 1
The main water quality characteristics of the high-concentration wastewater are as follows: the pH value of the waste water is 7, the conductivity is 10000 mu s/cm, and the COD iscr100mg/L，Na+2000mg/L，Cl-2500mg/L, total hardness (CaCO)3)1500mg/L, dissolved silicon 50mg/L, NH4-N0mg/L。
As shown in FIG. 1, the treatment process of the high concentration wastewater is as follows:
(1) and (5) nanofiltration. The high-concentration wastewater enters a nanofiltration unit for nanofiltration treatment, multivalent ions such as hardness and the like and part of organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters the step (2) for treatment, sodium carbonate is added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is subjected to concentrated drying treatment, the supernatant is subjected to activated carbon adsorption by adopting powdered activated carbon, and then the supernatant is returned to the nanofiltration unit and mixed with the high-concentration wastewater to enter the nanofiltration unit for circulation treatment;
wherein the adding amount of sodium carbonate is Ca2+: the molar ratio of sodium carbonate is 1: 1, adding the powdered activated carbon in the following amount: the mass ratio of COD is 2: 1;
the nanofiltration membrane component adopts a polyamide spiral wound membrane component; the operating conditions of the nanofiltration unit are as follows: the operating pressure of the feed liquid side is 0.5MPa, and the hardness of nanofiltration produced water is basically about 70 mg/L; under the operating conditions, the flux of the nanofiltration membrane is kept at 13-16L/m2H, the water recovery rate of the nanofiltration system is higher than 92 percent; the effluent hardness of the supernatant after sodium carbonate precipitation is less than 15 mg/L; supernatant COD after adsorption of powdered activated carboncrLess than 10 mg/L;
(2) high-efficiency reverse osmosis. Adjusting the pH value of nanofiltration produced water to 9 by using sodium hydroxide, and then, entering a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
wherein the high-efficiency reverse osmosis membrane module adopts a polyamide spiral-wound membrane module; in the operation process, the operating conditions of the high-efficiency reverse osmosis unit are as follows: the pH of the wastewater on the feed liquid side is 9, and the operating pressure on the feed liquid side is 2 MPa; under the operating conditions, the flux of the high-efficiency reverse osmosis membrane is kept between 17 and 22L/m2H, water recovery higher than 75%;
(3) and (4) membrane distillation. Adjusting the pH value of the high-efficiency reverse osmosis concentrated water to 7 by using hydrochloric acid, and then, entering a membrane distillation unit for deep concentration treatment to obtain membrane distillation produced water and membrane distillation concentrated water;
the membrane distillation component adopts a Polytetrafluoroethylene (PTFE) hollow fiber hydrophobic membrane component, the membrane aperture is 0.2 μm, and the membrane distillation form is internal pressure type vacuum membrane distillation. During operation, the operating conditions of the membrane distillation unit are as follows: the pH value of the wastewater on the feed liquid side is 7, the temperature of the wastewater on the feed liquid side is 65 ℃, the flow velocity of the membrane surface on the feed liquid side is 1.2m/s, and the permeationThe vacuum degree of the liquid permeating side is-0.095 MPa; under the operating conditions, the flux of the membrane distillation membrane is kept between 3 and 5L/m2H, water recovery higher than 75%;
(4) and (4) evaporating and crystallizing. And (3) carrying out evaporation crystallization treatment on the membrane distillation concentrated water, wherein an evaporation heat source adopts waste steam for heating, and salt crystals and evaporation crystallization water are obtained.
Wherein the water recovery rate of the evaporative crystallization unit is higher than 80%.
Wherein, the salt crystals are treated by centralized drying; the high-efficiency reverse osmosis produced water, the membrane distillation produced water and the evaporative crystallization produced water can be recycled for the production process; the activated carbon after the saturation adsorption in the step (1) can be directly used as fuel for combustion treatment.
The conductivity of the produced water of the whole system of the high-concentration wastewater treated by the method is less than or equal to 300 mu S/cm, and the COD of the produced watercr<10mg/L, and the water recovery rate of the whole system is higher than 93 percent.
Example 2
The main water quality characteristics of the high-concentration wastewater are as follows: the pH value of the wastewater is 7, the conductivity is 13000 mu s/cm, and the COD iscr150mg/L，Na+2000mg/L，Cl-2500mg/L, total hardness (CaCO)3)2000mg/L, dissolved silicon 50mg/L, NH4-N0mg/L。
As shown in FIG. 1, the treatment process of the high concentration wastewater is as follows:
(1) and (5) nanofiltration. The high-concentration wastewater enters a nanofiltration unit for nanofiltration treatment, multivalent ions such as hardness and the like and partial organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters the step (2) for treatment, sodium sulfate is added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is subjected to concentrated drying treatment, the supernatant is subjected to activated carbon adsorption by adopting granular activated carbon and then returns to the nanofiltration unit, the supernatant is mixed with the high-concentration wastewater and enters the nanofiltration unit for circulation treatment,
wherein,the addition amount of the sodium sulfate is Ca2+: the molar ratio of sodium sulfate is 1: 1, adding the granular activated carbon in the following amount: the mass ratio of COD is 10: 1, the effluent hardness of the supernatant after sodium sulfate precipitation is less than 20 mg/L; supernatant COD after granular activated carbon adsorptioncrLess than 10 mg/L;
the nanofiltration membrane component adopts a sulfonated polyether sulfone roll-type membrane component; the operating conditions of the nanofiltration unit are as follows: the operating pressure of the feed liquid side is 0.7MPa, and the hardness of nanofiltration produced water is basically about 80 mg/L; under the operating conditions, the flux of the nanofiltration membrane is kept at 15-18L/m2H, water recovery higher than 92%;
(2) high-efficiency reverse osmosis. Adjusting the pH value of nanofiltration produced water to 9.5 by using sodium hydroxide, and then, entering a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
wherein the high-efficiency reverse osmosis membrane module adopts a polyamide spiral-wound membrane module; in the operation process, the operating conditions of the high-efficiency reverse osmosis unit are as follows: the pH of the wastewater on the feed liquid side is 9.5, and the operating pressure on the feed liquid side is 2 MPa; under the operating conditions, the flux of the high-efficiency reverse osmosis membrane is kept between 18 and 22L/m2H, water recovery higher than 75%;
(3) and (4) membrane distillation. Adjusting the pH value of the high-efficiency reverse osmosis concentrated water to 7.5 by using hydrochloric acid, and then, entering a membrane distillation unit for deep concentration treatment to obtain membrane distillation produced water and membrane distillation concentrated water;
the membrane distillation component adopts a Polytetrafluoroethylene (PTFE) hollow fiber hydrophobic membrane component, the membrane aperture is 0.2 μm, and the membrane distillation form is internal pressure type vacuum membrane distillation. During operation, the operating conditions of the membrane distillation unit are as follows: the pH value of the wastewater on the feed liquid side is 7.5, the temperature of the wastewater on the feed liquid side is 75 ℃, the membrane surface flow rate on the feed liquid side is 0.8m/s, and the vacuum degree on the permeate side is-0.085 MPa; under the operating conditions, the flux of the membrane distillation membrane is kept between 4 and 6L/m2H, water recovery higher than 75%;
(4) and (4) evaporating and crystallizing. And (3) carrying out evaporation crystallization treatment on the membrane distillation concentrated water, wherein an evaporation heat source adopts waste steam for heating, and salt crystals and evaporation crystallization water are obtained.
Wherein the water recovery rate of the evaporative crystallization unit is higher than 80%.
Wherein, the salt crystals are treated by centralized drying; the high-efficiency reverse osmosis produced water, the membrane distillation produced water and the evaporative crystallization produced water can be recycled for the production process; the activated carbon after the saturation adsorption in the step (1) can be directly used as fuel for combustion treatment.
The conductivity of the produced water of the whole system of the high-concentration wastewater treated by the method is less than or equal to 300 mu S/cm, and the COD of the produced watercr<10mg/L, and the water recovery rate of the whole system is higher than 93 percent.
Example 3
The main water quality characteristics of the high-concentration wastewater are as follows: the pH value of the wastewater is 8, the conductivity is 15000 mu s/cm, and the COD iscr300mg/L，Na+3000mg/L，Cl-3500mg/L, Total hardness (CaCO)3)2500mg/L, 80mg/L of dissolved silicon, NH4-N3mg/L。
As shown in FIG. 1, the treatment process of the high concentration wastewater is as follows:
(1) and (5) nanofiltration. The high-concentration wastewater enters a nanofiltration unit for nanofiltration treatment, multivalent ions such as hardness and the like and partial organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters the step (2) for treatment, a mixture of sodium carbonate and sodium sulfate is added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is concentrated and dried, the supernatant is subjected to activated carbon adsorption by adopting powdered activated carbon and then returns to the nanofiltration unit, and the calcium slag is mixed with the high-concentration wastewater to enter the nanofiltration unit for circulation treatment,
wherein the addition amount of the mixture of sodium carbonate and sodium sulfate is Ca2+: the molar ratio of the mixture of sodium carbonate and sodium sulphate is 1: 1, adding the powdered activated carbon in the following amount: the mass ratio of COD is 8: 1; after precipitation with a mixture of sodium carbonate and sodium sulphateThe effluent hardness of the supernatant is less than 15 mg/L; supernatant COD after adsorption of powdered activated carboncrLess than 10 mg/L;
the nanofiltration membrane component adopts a polyamide spiral wound membrane component; the operating conditions of the nanofiltration unit are as follows: the operating pressure of the feed liquid side is 0.8MPa, and the hardness of nanofiltration produced water is basically about 90 mg/L; under the operating conditions, the flux of the nanofiltration membrane is kept at 14-18L/m2H, water recovery higher than 92%;
(2) high-efficiency reverse osmosis. Adjusting the pH value of nanofiltration produced water to 10 by using sodium hydroxide, and then, entering a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
wherein the high-efficiency reverse osmosis membrane module adopts a polyamide spiral-wound membrane module; in the operation process, the operating conditions of the high-efficiency reverse osmosis unit are as follows: the pH of the wastewater on the feed liquid side is 10, and the operating pressure on the feed liquid side is 3 MPa; under the operating conditions, the flux of the high-efficiency reverse osmosis membrane is kept between 15 and 19L/m2H, water recovery higher than 75%;
(3) and (4) membrane distillation. Adjusting the pH value of the high-efficiency reverse osmosis concentrated water to 8 by using hydrochloric acid, and then, entering a membrane distillation unit for deep concentration treatment to obtain membrane distillation produced water and membrane distillation concentrated water;
the membrane distillation component adopts a polypropylene (PP) hollow fiber hydrophobic membrane component, the aperture of the membrane is 0.2 mu m, and the membrane distillation form is internal pressure type vacuum membrane distillation. During operation, the operating conditions of the membrane distillation unit are as follows: the pH of the wastewater on the feed liquid side is 8, the temperature of the wastewater on the feed liquid side is 85 ℃, the flow rate of the membrane surface on the feed liquid side is 1.0m/s, and the vacuum degree on the permeate side is-0.075 MPa; under the operating conditions, the flux of the membrane distillation membrane is kept between 4 and 6L/m2H, water recovery higher than 75%;
(4) and (4) evaporating and crystallizing. And (3) carrying out evaporation crystallization treatment on the membrane distillation concentrated water, wherein an evaporation heat source adopts electric heating to obtain salt crystals and evaporation crystallization water.
Wherein the water recovery rate of the evaporative crystallization unit is higher than 80%.
Wherein, the salt crystals are treated by centralized drying; the high-efficiency reverse osmosis produced water, the membrane distillation produced water and the evaporative crystallization produced water can be recycled for the production process; the activated carbon after the saturation adsorption in the step (1) can be directly used as fuel for combustion treatment.
The conductivity of the produced water of the whole system of the high-concentration wastewater treated by the method is less than or equal to 300 mu S/cm, and the COD of the produced watercr<10mg/L, and the water recovery rate of the whole system is higher than 93 percent.
Example 4
The water quality of the high-concentration wastewater is characterized in that: the pH value of the wastewater is 9, the conductivity is 20000 mu s/cm, and the COD iscr500mg/L，Na+4000mg/L，Cl-5000mg/L, total hardness (CaCO)3)3000mg/L, dissolved silicon 100mg/L, NH4-N5mg/L；
As shown in FIG. 1, the treatment process of the high concentration wastewater is as follows:
(1) and (5) nanofiltration. The high-concentration wastewater enters a nanofiltration unit for nanofiltration treatment, multivalent ions such as hardness and the like and partial organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters the step (2) for treatment, sodium carbonate is added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is concentrated and dried, the supernatant is subjected to activated carbon adsorption by adopting powdered activated carbon and then returns to the nanofiltration unit, and the supernatant is mixed with the high-concentration wastewater and enters the nanofiltration unit for circulation treatment,
wherein the adding amount of sodium carbonate is Ca2+: the molar ratio of sodium carbonate is 1: 1, adding the powdered activated carbon in the following amount: the mass ratio of COD is 8: 1; the effluent hardness of the supernatant after sodium carbonate precipitation is less than 15 mg/L; supernatant COD after adsorption of powdered activated carboncrLess than 10 mg/L;
the nanofiltration membrane component adopts a polyamide spiral wound membrane component; the operating conditions of the nanofiltration unit are as follows: the operating pressure of the feed liquid side is 1.0MPa, and the water hardness is produced by nanofiltrationBasically about 100 mg/L; under the operating conditions, the flux of the nanofiltration membrane is kept at 15-18L/m2H, water recovery higher than 92%;
(2) high-efficiency reverse osmosis. Adjusting the pH value of nanofiltration produced water to 11 by using sodium hydroxide, and then, entering a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
wherein the high-efficiency reverse osmosis membrane module adopts a polyamide spiral-wound membrane module; in the operation process, the operating conditions of the high-efficiency reverse osmosis unit are as follows: the pH of the wastewater on the feed liquid side is 11, and the operating pressure on the feed liquid side is 5 MPa; under the operating conditions, the flux of the high-efficiency reverse osmosis membrane is kept between 16 and 22L/m2H, water recovery higher than 75%;
(3) and (4) membrane distillation. Adjusting the pH value of the high-efficiency reverse osmosis concentrated water to 9 by using hydrochloric acid, and then, feeding the high-efficiency reverse osmosis concentrated water into a membrane distillation unit for deep concentration treatment to obtain membrane distillation produced water and membrane distillation concentrated water;
the membrane distillation component adopts a polypropylene (PP) hollow fiber hydrophobic membrane component, the aperture of the membrane is 0.15 mu m, and the membrane distillation form is internal pressure type vacuum membrane distillation. During operation, the operating conditions of the membrane distillation unit are as follows: the pH of the wastewater on the feed liquid side is 9, the temperature of the wastewater on the feed liquid side is 85 ℃, the membrane surface flow rate on the feed liquid side is 0.6m/s, and the vacuum degree on the permeate side is-0.09 MPa; under the operating conditions, the flux of the membrane distillation membrane is kept between 5 and 7L/m2H, water recovery higher than 75%;
(4) and (4) evaporating and crystallizing. And (3) carrying out evaporation crystallization treatment on the membrane distillation concentrated water, wherein an evaporation heat source adopts waste steam for heating, and salt crystals and evaporation crystallization water are obtained.
Wherein the water recovery rate of the evaporative crystallization unit is higher than 80%.
Wherein, the salt crystals are treated by centralized drying; the high-efficiency reverse osmosis produced water, the membrane distillation produced water and the evaporative crystallization produced water can be recycled for the production process; the activated carbon after the saturation adsorption in the step (1) can be directly used as fuel for combustion treatment.
The conductivity of the produced water of the whole system of the high-concentration wastewater treated by the method is less than or equal to 300 mu S/cm, and the COD of the produced watercr<10mg/L, and the water recovery rate of the whole system is higher than 93 percent.
Example 5
The water quality of the high-concentration wastewater is characterized in that: the pH value of the waste water is 7, the conductivity is 10000 mu s/cm, and the COD iscr100mg/L，Na+2000mg/L，Cl-2500mg/L, total hardness (CaCO)3)1500mg/L, dissolved silicon 50mg/L, NH4-N0mg/L。
As shown in FIG. 1, the treatment process of the high concentration wastewater is as follows:
(1) and (5) nanofiltration. The high-concentration wastewater enters a nanofiltration unit for nanofiltration treatment, multivalent ions such as hardness and the like and partial organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters the step (2) for treatment, sodium carbonate is added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is concentrated and dried, the supernatant is subjected to activated carbon adsorption by adopting powdered activated carbon and then returns to the nanofiltration unit, and the supernatant is mixed with the high-concentration wastewater and enters the nanofiltration unit for circulation treatment,
wherein the adding amount of sodium carbonate is Ca2+: the molar ratio of sodium carbonate is 1: 1, adding the powdered activated carbon in the following amount: the mass ratio of COD is 5: 1; the effluent hardness of the supernatant after sodium carbonate precipitation is less than 15 mg/L; supernatant COD after adsorption of powdered activated carboncrLess than 10 mg/L;
the nanofiltration membrane component adopts a polyamide spiral wound membrane component; the operating conditions of the nanofiltration unit are as follows: the operating pressure of the feed liquid side is 0.5MPa, and the hardness of nanofiltration produced water is basically about 70 mg/L; under the operating conditions, the flux of the nanofiltration membrane is kept at 13-16L/m2H, water recovery higher than 92%;
(2) high-efficiency reverse osmosis. Adjusting the pH value of nanofiltration produced water to 10 by using sodium hydroxide, and then, entering a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
wherein the high-efficiency reverse osmosis membrane module adopts a polyamide spiral-wound membrane module; in the operation process, the operating conditions of the high-efficiency reverse osmosis unit are as follows: the pH of the wastewater on the feed liquid side is 10, and the operating pressure on the feed liquid side is 2 MPa; under the operating conditions, the flux of the high-efficiency reverse osmosis membrane is kept between 17 and 22L/m2H, water recovery higher than 75%;
(3) and (4) membrane distillation. Adjusting the pH value of the high-efficiency reverse osmosis concentrated water to 9 by using hydrochloric acid, and then, feeding the high-efficiency reverse osmosis concentrated water into a membrane distillation unit for deep concentration treatment to obtain membrane distillation produced water and membrane distillation concentrated water;
the membrane distillation component adopts a Polytetrafluoroethylene (PTFE) hollow fiber hydrophobic membrane component, the membrane aperture is 0.18 mu m, and the membrane distillation form is internal pressure type vacuum membrane distillation. During operation, the operating conditions of the membrane distillation unit are as follows: the pH value of the wastewater on the feed liquid side is 9, the temperature of the wastewater on the feed liquid side is 80 ℃, the membrane surface flow rate on the feed liquid side is 0.9m/s, and the vacuum degree on the permeate side is-0.09 MPa; under the operating conditions, the flux of the membrane distillation membrane is kept between 7 and 10L/m2H, water recovery higher than 75%;
(4) and (4) evaporating and crystallizing. And (3) carrying out evaporation crystallization treatment on the membrane distillation concentrated water, wherein an evaporation heat source adopts waste steam for heating, and salt crystals and evaporation crystallization water are obtained.
Wherein the water recovery rate of the evaporative crystallization unit is higher than 80%.
Wherein, the salt crystals are treated by centralized drying; the high-efficiency reverse osmosis produced water, the membrane distillation produced water and the evaporative crystallization produced water can be recycled for the production process; the activated carbon after the saturation adsorption in the step (1) can be directly used as fuel for combustion treatment.
The conductivity of the produced water of the whole system of the high-concentration wastewater treated by the method is less than or equal to 300 mu S/cm, and the COD of the produced watercr<10mg/L, and the water recovery rate of the whole system is higher than 93 percent.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not intended to limit the scope of the present invention, so that all equivalent variations made by using the contents of the specification and drawings are included in the scope of the present invention.
Those not described in detail in this specification are within the skill of the art.
Claims (20)
1. The zero discharge method of the high-concentration wastewater is characterized by comprising the following steps:
(1) and (4) nanofiltration: the high-concentration wastewater enters a nanofiltration unit for nanofiltration filtration treatment, multivalent ions such as hardness and the like and part of organic matters in the high-concentration wastewater are removed to obtain nanofiltration produced water and nanofiltration concentrated water, the nanofiltration produced water enters a sedimentation tank for treatment in the step (2), salts are added into the nanofiltration concentrated water to precipitate calcium ions to obtain calcium slag, the calcium slag is subjected to centralized drying treatment, supernatant in the sedimentation tank enters an activated carbon adsorption unit for activated carbon adsorption, and then the adsorbed produced water returns to the nanofiltration unit and is mixed with the high-concentration wastewater to enter the nanofiltration unit for circulation treatment;
(2) efficient reverse osmosis: the nanofiltration produced water is subjected to alkali adjustment treatment, and then enters a high-efficiency reverse osmosis unit for further concentration and separation to obtain high-efficiency reverse osmosis produced water and high-efficiency reverse osmosis concentrated water;
(3) membrane distillation: carrying out acid regulation treatment on the high-efficiency reverse osmosis concentrated water, and then, carrying out deep concentration treatment on the high-efficiency reverse osmosis concentrated water in a membrane distillation unit to obtain membrane distillation produced water and membrane distillation concentrated water;
(4) evaporation and crystallization: and (4) the membrane distillation concentrated water enters an evaporation crystallization unit for evaporation crystallization treatment to obtain salt crystals and evaporation crystallization water.
2. The method for zero discharge of high concentration wastewater of claim 1, wherein: the high-efficiency reverse osmosis water production, the membrane distillation water production and the evaporative crystallization water production can be recycled for the production process.
3. The method for zero discharge of high concentration wastewater of claim 1, wherein: the main water quality characteristics of the high-concentration wastewater are as follows: pH 7-9, conductivity 10000-20000 mu s/cm, CODcr100～500mg/L，Na+2000～4000mg/L，Cl-2500-5000 mg/L, total hardness (CaCO)3) 1500-3000 mg/L and 50-100 mg/L of silicon solution.
4. The method for zero discharge of high concentration wastewater of claim 1, wherein: in the nanofiltration unit in the step (1), the nanofiltration membrane component adopts a roll-type membrane component, and the nanofiltration membrane material is polyamide or sulfonated polyether sulfone.
5. The method for zero discharge of high concentration wastewater of claim 1, wherein: the operating conditions of the nanofiltration unit in the step (1) are as follows: the operating pressure of the feed liquid side is 0.5-1 MPa.
6. The method for zero discharge of high concentration wastewater according to claim 1,the method is characterized in that: the salt in the step (1) is sodium sulfate or sodium carbonate or a mixture of the sodium sulfate and the sodium carbonate, and the adding amount of the salt needs to meet the following requirements: ca2+: the molar ratio of the salts is 1: 1.
7. the method for zero discharge of high concentration wastewater of claim 1, wherein: the activated carbon in the step (1) is powdered activated carbon or granular activated carbon, and the adding amount of the activated carbon needs to meet the following requirements: activated carbon: the mass ratio of COD is 2: 1-10: 1, the activated carbon after saturated adsorption can be directly used as fuel for combustion treatment.
8. The method for zero discharge of high concentration wastewater of claim 1, wherein: the high-concentration wastewater is treated by the nanofiltration unit, and the water recovery rate is higher than 92%.
9. The method for zero discharge of high concentration wastewater of claim 1, wherein: and (3) the alkali adjustment treatment in the step (2) is to adjust the pH of the nanofiltration water to 9-11 by using sodium hydroxide.
10. The method for zero discharge of high concentration wastewater of claim 1, wherein: the operation conditions of the high-efficiency reverse osmosis unit in the step (2) are as follows: the pH of the wastewater on the feed liquid side is 9-11, and the operating pressure on the feed liquid side is 2-5 MPa.
11. The method for zero discharge of high concentration wastewater of claim 1, wherein: in the high-efficiency reverse osmosis unit in the step (2), the membrane component of the high-efficiency reverse osmosis is in the form of a roll-type membrane component, and the membrane material is polyamide; the high-efficiency reverse osmosis components are in one group, or a plurality of groups are connected in series, or a plurality of groups are connected in parallel.
12. The method for zero discharge of high concentration wastewater of claim 1, wherein: the nanofiltration produced water after the alkali adjustment treatment is treated by a high-efficiency reverse osmosis unit, and the water recovery rate is higher than 75%.
13. The method for zero discharge of high concentration wastewater of claim 1, wherein: and (4) the acid adjusting treatment in the step (3) is to adjust the pH of the high-efficiency reverse osmosis concentrated water to 7-9 by using hydrochloric acid.
14. The method for zero discharge of high concentration wastewater of claim 1, wherein: the operation conditions of the membrane distillation unit in the step (3) are as follows: the pH value of the wastewater on the feed liquid side is 7-9, the temperature of the wastewater on the feed liquid side is 65-85 ℃, the membrane surface flow rate on the feed liquid side is 0.6-1.2 m/s, and the vacuum degree on the permeate side is-0.075-0.095 MPa.
15. The method for zero discharge of high concentration wastewater of claim 1, wherein: in the membrane distillation unit in the step (3), the membrane material of the membrane distillation assembly is polyvinylidene fluoride, polytetrafluoroethylene or polypropylene; the pore diameter of the membrane is 0.15-0.2 μm.
16. The method for zero discharge of high concentration wastewater of claim 1, wherein: the membrane distillation module is in the form of a hollow fiber or a plate.
17. The method for zero discharge of high concentration wastewater of claim 1, wherein: the membrane distillation form is internal pressure type vacuum membrane distillation; the membrane distillation components are in one group, or a plurality of groups are connected in series, or a plurality of groups are connected in parallel.
18. The method for zero discharge of high concentration wastewater of claim 1, wherein: the high-efficiency reverse osmosis concentrated water subjected to the acid adjusting treatment is treated by a membrane distillation unit, and the water recovery rate is higher than 75%.
19. The method for zero discharge of high concentration wastewater of claim 1, wherein: in the step (4), the evaporative crystallization unit adopts the existing commercial evaporative crystallizer, and the heat source adopts waste steam heating or electric heating.
20. The method for zero discharge of high concentration wastewater of claim 1, wherein: the membrane distillation concentrated water is treated by an evaporation crystallization unit, and the water recovery rate is higher than 80%.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1236330A (en) * | 1996-08-12 | 1999-11-24 | 德巴斯什·穆霍帕德黑 | Method and apparatus for high efficiency reverse osmosis operation |
| CN101708911A (en) * | 2009-11-23 | 2010-05-19 | 苏州凯新分离科技有限公司 | Desulfuration waste water treatment process with membrane method |
| CN101811798A (en) * | 2010-03-23 | 2010-08-25 | 中国市政工程华北设计研究总院 | Method for improving security of water quality by utilizing microorganism-membrane compound technology |
| CN103601327A (en) * | 2013-09-30 | 2014-02-26 | 宁夏宝塔石化科技实业发展有限公司 | Near-zero-emission treating method and device for salt-containing waste water of refinery enterprise |
-
2014
- 2014-06-18 CN CN201410273247.0A patent/CN105198143B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1236330A (en) * | 1996-08-12 | 1999-11-24 | 德巴斯什·穆霍帕德黑 | Method and apparatus for high efficiency reverse osmosis operation |
| CN101708911A (en) * | 2009-11-23 | 2010-05-19 | 苏州凯新分离科技有限公司 | Desulfuration waste water treatment process with membrane method |
| CN101811798A (en) * | 2010-03-23 | 2010-08-25 | 中国市政工程华北设计研究总院 | Method for improving security of water quality by utilizing microorganism-membrane compound technology |
| CN103601327A (en) * | 2013-09-30 | 2014-02-26 | 宁夏宝塔石化科技实业发展有限公司 | Near-zero-emission treating method and device for salt-containing waste water of refinery enterprise |
Non-Patent Citations (1)
| Title |
|---|
| 王平 编: "《污水回用与火电厂循环冷却水处理技术问答》", 31 March 2013, 中国电力出版社 * |
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