CN112624505A - Treatment method and system for evaporation mother liquor of high-salt-content wastewater - Google Patents
Treatment method and system for evaporation mother liquor of high-salt-content wastewater Download PDFInfo
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- CN112624505A CN112624505A CN202011493819.8A CN202011493819A CN112624505A CN 112624505 A CN112624505 A CN 112624505A CN 202011493819 A CN202011493819 A CN 202011493819A CN 112624505 A CN112624505 A CN 112624505A
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- 239000012452 mother liquor Substances 0.000 title claims abstract description 109
- 238000001704 evaporation Methods 0.000 title claims abstract description 107
- 230000008020 evaporation Effects 0.000 title claims abstract description 94
- 239000002351 wastewater Substances 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000001728 nano-filtration Methods 0.000 claims abstract description 178
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 140
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims abstract description 93
- 229910052938 sodium sulfate Inorganic materials 0.000 claims abstract description 87
- 235000011152 sodium sulphate Nutrition 0.000 claims abstract description 87
- 150000003839 salts Chemical class 0.000 claims abstract description 75
- 239000011780 sodium chloride Substances 0.000 claims abstract description 69
- 238000002425 crystallisation Methods 0.000 claims abstract description 50
- 230000008025 crystallization Effects 0.000 claims abstract description 50
- 238000007710 freezing Methods 0.000 claims abstract description 29
- 230000008014 freezing Effects 0.000 claims abstract description 29
- 239000005416 organic matter Substances 0.000 claims abstract description 29
- 238000010790 dilution Methods 0.000 claims abstract description 17
- 239000012895 dilution Substances 0.000 claims abstract description 17
- 238000010992 reflux Methods 0.000 claims abstract description 12
- 239000000047 product Substances 0.000 claims abstract description 8
- 238000007865 diluting Methods 0.000 claims abstract description 4
- 239000000706 filtrate Substances 0.000 claims abstract description 4
- 239000012530 fluid Substances 0.000 claims abstract description 4
- 239000010446 mirabilite Substances 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 135
- 239000012528 membrane Substances 0.000 claims description 59
- 238000004519 manufacturing process Methods 0.000 claims description 19
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 14
- 238000001223 reverse osmosis Methods 0.000 claims description 13
- 230000003647 oxidation Effects 0.000 claims description 6
- 238000007254 oxidation reaction Methods 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 238000012545 processing Methods 0.000 claims description 4
- 235000002639 sodium chloride Nutrition 0.000 description 118
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 17
- 229910002651 NO3 Inorganic materials 0.000 description 16
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 239000013078 crystal Substances 0.000 description 12
- 238000000926 separation method Methods 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 230000001105 regulatory effect Effects 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 239000010842 industrial wastewater Substances 0.000 description 7
- 238000004062 sedimentation Methods 0.000 description 7
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 241000894006 Bacteria Species 0.000 description 6
- 239000003456 ion exchange resin Substances 0.000 description 6
- 229920003303 ion-exchange polymer Polymers 0.000 description 6
- 239000012266 salt solution Substances 0.000 description 6
- 238000004140 cleaning Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 208000028659 discharge Diseases 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 239000010802 sludge Substances 0.000 description 4
- 238000004065 wastewater treatment Methods 0.000 description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229920001429 chelating resin Polymers 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 210000003298 dental enamel Anatomy 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000013024 dilution buffer Substances 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- YPJKMVATUPSWOH-UHFFFAOYSA-N nitrooxidanyl Chemical compound [O][N+]([O-])=O YPJKMVATUPSWOH-UHFFFAOYSA-N 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000000108 ultra-filtration Methods 0.000 description 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000003851 biochemical process Effects 0.000 description 1
- ZFXVRMSLJDYJCH-UHFFFAOYSA-N calcium magnesium Chemical compound [Mg].[Ca] ZFXVRMSLJDYJCH-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000001640 fractional crystallisation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000005374 membrane filtration Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- -1 salt ions Chemical class 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Inorganic materials [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000004075 wastewater filtration Methods 0.000 description 1
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
- C01D3/14—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
- C02F1/02—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
- C02F1/22—Treatment of water, waste water, or sewage by freezing
-
- 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
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- 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
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- 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
- C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic 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
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/101—Sulfur compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/12—Halogens or halogen-containing compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/163—Nitrates
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/08—Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/006—Regulation methods for biological treatment
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- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
Abstract
The invention discloses a treatment method of evaporation mother liquor of high-salt-content wastewater, which comprises the following steps: carrying out nanofiltration treatment on the high-salt-content wastewater after pretreatment, carrying out evaporative crystallization treatment on filtrate to separate out sodium chloride product salt to obtain sodium chloride evaporative mother liquor, evaporating and concentrating trapped fluid, and carrying out freezing crystallization treatment to separate out mirabilite to obtain sodium sulfate frozen mother liquor; continuously evaporating and crystallizing the sodium sulfate freezing mother liquor to separate out sodium sulfate and sodium chloride mixed salt to obtain sodium sulfate evaporating mother liquor, dissolving and diluting the mixed salt, and refluxing to a nanofiltration system; and sequentially carrying out organic matter treatment, dilution and biochemical treatment on the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor, then refluxing to a pretreatment system, and then entering a nanofiltration system for nanofiltration treatment. The invention discloses a high-salt-content wastewater evaporation mother liquor treatment system.
Description
Technical Field
The invention relates to the field of wastewater treatment, in particular to a method and a system for treating high-salt-content wastewater evaporation mother liquor.
Background
Among the numerous high-salt-content industrial wastewater quality-separating salt zero-discharge treatment methods, a nanofiltration and thermal method coupled two-stage salt separation method, a freezing and thermal method coupled fractional crystallization salt separation method and a (sodium sulfate and sodium chloride) mixed salt dissolving and refluxing process are combined, so that the method has the advantages of high salt separation purity, relatively high salt separation efficiency, high quality-separating crystallized salt yield and the like, and is accepted by industry people and industry experts.
In the actual operation process, the purity of the sodium chloride and sodium sulfate crystal salt separated by the two salt separation methods basically meets the requirement of industrial salt. Sodium chloride and sodium sulfate evaporation mother liquor partially flows back to the nanofiltration system, the residual evaporation mother liquor forms miscellaneous salt after passing through a miscellaneous salt evaporation crystallization system, and a large amount of evaporation mother liquor refluxed by the method can impact the nanofiltration system, thereby influencing the stability of system operation and increasing energy consumption. And impurities contained in the evaporation mother liquor can be accumulated in the nanofiltration system along with the reflux, so that the operation load of the system is caused, and the follow-up is influenced. Meanwhile, a large amount of miscellaneous salt can be generated by the residual evaporation mother liquor, and the miscellaneous salt is qualitatively treated as dangerous waste, so that the environmental protection pressure of enterprises and the wastewater treatment cost are increased.
Disclosure of Invention
Therefore, a need exists for a method and a system for treating the evaporation mother liquor of the high-salt-content wastewater, which aim to solve the problem of treatment of the evaporation mother liquor.
A treatment method of evaporation mother liquor of high-salt-content wastewater comprises the following steps:
carrying out nanofiltration treatment on the high-salt-content wastewater after pretreatment, carrying out evaporative crystallization treatment on filtrate to separate out sodium chloride product salt to obtain sodium chloride evaporative mother liquor, evaporating and concentrating trapped fluid, and carrying out freezing crystallization treatment to separate out mirabilite to obtain sodium sulfate frozen mother liquor;
continuously evaporating and crystallizing the sodium sulfate freezing mother liquor to separate out sodium sulfate and sodium chloride mixed salt to obtain sodium sulfate evaporating mother liquor, dissolving and diluting the mixed salt, and refluxing to a nanofiltration system;
and sequentially carrying out organic matter treatment, dilution and biochemical treatment on the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor, then refluxing to a pretreatment system, and then entering a nanofiltration system for nanofiltration treatment.
In some embodiments, the step of treating the organic matter is ozone contact oxidation, and the ratio of the mass of the added ozone to the total mass of COD in the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor is O3：COD＝(0.8～1.2):1。
In some embodiments, the method further comprises the step of adjusting the pH value of the diluted evaporation mother liquor to 6.5-7.5 before biochemical treatment.
In some of these embodiments, the temperature of the biochemical treatment is 10 ℃ to 40 ℃.
A high salt content waste water evaporation mother liquor treatment system of a treatment method of high salt content waste water comprises the following steps:
the nanofiltration system is used for separating sodium chloride and sodium sulfate in the high-salt-content wastewater;
the sodium chloride evaporation crystallization system is provided with a sodium chloride concentrated water inlet and a sodium chloride evaporation mother liquor outlet which are communicated with a sodium chloride water outlet of the nanofiltration system;
the sodium sulfate evaporation and freezing crystallization system is provided with a sodium sulfate concentrated water inlet and a sodium sulfate evaporation mother liquor outlet which are communicated with a sodium sulfate water outlet of the nanofiltration system;
the device comprises an organic matter treatment system, a dilution tank and a biochemical treatment system which are sequentially communicated, wherein the nanofiltration system, the sodium chloride evaporative crystallization system, the organic matter treatment system, the dilution tank and the biochemical treatment system form a first closed loop, and the nanofiltration system, the sodium sulfate evaporative freezing crystallization system, the organic matter treatment system, the dilution tank and the biochemical treatment system form a second closed loop;
the nanofiltration system, the sodium sulfate evaporation freezing crystallization system and the dissolving tank form a third closed loop.
In some embodiments, the nanofiltration system comprises a nanofiltration water inlet pump, a cartridge filter, a nanofiltration high-pressure pump and a nanofiltration membrane which are connected in sequence.
In some embodiments, the device further comprises a nanofiltration water production tank and a nanofiltration concentrated water tank which are respectively connected with the nanofiltration membrane, wherein the nanofiltration water production tank is connected with the sodium chloride evaporative crystallization system, and the nanofiltration concentrated water tank is connected with the sodium sulfate evaporative freezing crystallization system.
In some of these embodiments, the nanofiltration water inlet pump comprises a first nanofiltration water inlet pump and a second nanofiltration water inlet pump, the security filter comprises a first security filter and a second security filter, the nanofiltration high-pressure pump comprises a first nanofiltration high-pressure pump and a second nanofiltration high-pressure pump, the nanofiltration membrane comprises a first nanofiltration membrane and a second nanofiltration membrane, the first nanofiltration water inlet pump, the first security filter, the first nanofiltration high-pressure pump, the first nanofiltration membrane, the second nanofiltration water inlet pump, the second security filter, the second nanofiltration high-pressure pump and the second nanofiltration membrane are sequentially connected, the first nanofiltration membrane and the second nanofiltration membrane are respectively connected with the nanofiltration water production tank, and the first nanofiltration membrane and the second nanofiltration membrane are respectively connected with the nanofiltration concentrated water production tank.
In some embodiments, the nanofiltration membrane filtration device comprises a washing water tank, and the washing water tank is connected with the nanofiltration membrane.
In some embodiments, a reverse osmosis membrane is arranged between the nanofiltration water production tank and the sodium chloride evaporative crystallization system.
Compared with the prior art, the invention removes nitrate radical and COD in the mother liquor by passing all the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor through the organic matter treatment system and the biochemical treatment system, then the nitrate radical and the COD in the mother liquor flow back to the pretreatment system and then enter the nanofiltration system, thereby avoiding the impact on the nanofiltration system, generating mixed salt (consisting of sodium sulfate and sodium chloride) by the evaporation crystallization system before the sodium sulfate evaporation mother liquor enters the organic matter treatment system and the biochemical treatment system, and the mixed salt flows back to the nanofiltration system after being dissolved by the dissolving tank, greatly reducing the salt content of the organic matter treatment mother liquor and the biochemical treatment mother liquor, thereby improving the effects of the organic matter treatment and the biochemical treatment and reducing the investment and the treatment cost. Because the concentration of nitrate and COD in the mother liquor is too high, the mother liquor firstly enters the dilution buffer tank to reduce the concentration of nitrate and COD, and the effect of entering the biochemical treatment system for treatment is improved.
Drawings
FIG. 1 is a schematic structural diagram of a high salinity wastewater evaporation mother liquor treatment system according to one embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a high salinity wastewater evaporation mother liquor treatment system according to another embodiment of the invention.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "coupled" to another element, it can be directly coupled to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The embodiment of the invention provides a treatment method of high-salt-content wastewater evaporation mother liquor, which comprises the following steps:
carrying out nanofiltration treatment on the high-salt-content wastewater after pretreatment, carrying out evaporative crystallization treatment on filtrate to separate out sodium chloride product salt to obtain sodium chloride evaporative mother liquor, evaporating and concentrating trapped fluid, and carrying out freezing crystallization treatment to separate out mirabilite to obtain sodium sulfate frozen mother liquor;
continuously evaporating and crystallizing the sodium sulfate freezing mother liquor to separate out sodium sulfate and sodium chloride mixed salt to obtain sodium sulfate evaporating mother liquor, dissolving and diluting the mixed salt, and refluxing to a nanofiltration system;
and sequentially carrying out organic matter treatment, dilution and biochemical treatment on the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor, then refluxing to a pretreatment system, and then entering a nanofiltration system for nanofiltration treatment.
Referring to fig. 1 and fig. 2, an embodiment of the present invention further provides a high salt-containing wastewater evaporation mother liquor treatment system for the treatment method of the high salt-containing wastewater evaporation mother liquor, including:
the nanofiltration system is used for separating sodium chloride and sodium sulfate in the high-salt-content wastewater;
the sodium chloride evaporation crystallization system 210 is provided with a sodium chloride concentrated water inlet and a sodium chloride evaporation mother liquor outlet which are communicated with a sodium chloride water outlet of the nanofiltration system;
a sodium sulfate evaporation freezing crystallization system 310 having a sodium sulfate concentrated water inlet and a sodium sulfate evaporation mother liquor outlet in communication with the sodium sulfate water outlet of the nanofiltration system;
the system comprises an organic matter treatment system 400, a dilution tank 500 and a biochemical treatment system 600 which are sequentially communicated, wherein a nanofiltration system, a sodium chloride evaporative crystallization system 210, the organic matter treatment system 400, the dilution tank 500 and the biochemical treatment system 600 form a first closed loop, and a nanofiltration system, a sodium sulfate evaporative freezing crystallization system 310, the organic matter treatment system 400, the dilution tank 500 and the biochemical treatment system 600 form a second closed loop;
the dissolution tank 800, the nanofiltration system, the sodium sulfate evaporative freezing crystallization system 310, and the dilution tank 500 form a third closed loop.
Compared with the prior art, the invention removes nitrate and COD in the mother liquor by passing all the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor through the organic matter treatment system 400 and the biochemical treatment system 600, then reflows to the pretreatment system and enters the nanofiltration system, thereby avoiding the impact on the nanofiltration system, and the sodium sulfate freezing mother liquor generates mixed salt consisting of sodium chloride and sodium sulfate and the sodium sulfate evaporation mother liquor by the sodium sulfate evaporation freezing crystallization system 310 again before the organic matter treatment and the biochemical process treatment, and the mixed salt reflows to the nanofiltration system after being dissolved by the dissolving tank 800, thereby greatly reducing the salt content of the organic matter treatment and biochemical treatment mother liquor, improving the effects of the organic matter treatment and the biochemical treatment, and reducing the investment and the treatment cost. Because the concentration of nitrate and COD in the mother liquor is too high, the mother liquor firstly enters the dilution buffer tank to reduce the concentration of nitrate and COD, and the effect of the mother liquor entering the biochemical treatment system 600 is improved.
The sodium sulfate freezing mother liquor mainly contains sodium sulfate, sodium chloride, nitrate, COD and the like, and due to the precipitation characteristic difference of the nitrate, the sodium sulfate and the sodium chloride, the mother liquor is continuously evaporated to precipitate sodium chloride and sodium sulfate mixed salt, and the mixed salt is relatively pure and contains a small amount of COD, nitrate and other impurities (single salt is separated after returning to the front end), so that the salt content of the evaporation mother liquor is reduced, and the subsequent organic matter treatment and biochemical treatment (the reaction system is reduced, and the investment and treatment cost are reduced) are facilitated. After the sodium sulfate crystal is separated out from the sodium sulfate freezing mother liquor, the secondary mother liquor (sodium sulfate evaporation mother liquor) of mixed salt (sodium chloride and sodium sulfate) can be continuously evaporated and separated out in the original evaporation system, and then all the secondary mother liquor enters the organic matter treatment.
In some embodiments, the front end of the nanofiltration system is provided with a pretreatment system, which may comprise a high density settling tank, an ultrafiltration device, a (preliminary) membrane concentration device, and an ion exchange resin (not shown). Feeding the incoming water into a high-density sedimentation tank by a centrifugal pump, feeding PFS, sodium carbonate, sodium hydroxide and PAM medicaments by a metering pump in sequence through variable frequency control, controlling the pH value of the incoming water to be 10-10.5, removing suspended matters and calcium-magnesium hardness in the incoming water, and feeding sulfuric acid into the high-density sedimentation tank to adjust the pH value of the produced water to be 7-7.5 through variable frequency control of the metering pump. The high-density sedimentation tank can also be provided with a sludge reflux pump and a sludge discharge pump to adjust and control the sedimentation effect.
The primary membrane concentration device can adopt a single-stage two-stage combined desalination membrane element, a common centrifugal pump is used as a water inlet pump, a vertical multistage centrifugal pump is driven by frequency conversion and is used as a booster pump, and the recovery rate of the common regulating valve regulating device is increased. The water produced by the device is sent into a total water production pipe and then enters a nanofiltration system. The device concentrated water is sent into a device concentrated water tank.
After being homogenized and regulated by a concentrated water tank, the mixture is sent into ion exchange resin by a centrifugal pump. The ion exchange resin adopts a lower inlet and upper outlet mode, calcium and magnesium hardness in the concentrated water is removed by layered adsorption of common sodium type and chelating resin, and then the concentrated water enters a nanofiltration system.
The nanofiltration system utilizes the southward effect and the aperture screening principle of the nanofiltration membrane to realize the separation of monovalent salt and high-valent salt in the high-salt wastewater, and nanofiltration product water and nanofiltration concentrated water are obtained.
In some embodiments, the nanofiltration system comprises a nanofiltration water inlet pump, a cartridge filter, a nanofiltration high-pressure pump and a nanofiltration membrane connected in sequence.
In some embodiments, a nanofiltration water production tank 220 and a nanofiltration concentrated water tank 320 are respectively connected with the nanofiltration membrane, the nanofiltration water production tank 220 is connected with the sodium chloride evaporative crystallization system 210, and the nanofiltration concentrated water tank 320 is connected with the sodium sulfate evaporative freeze crystallization system 310.
In some embodiments, the nanofiltration water inlet pump comprises a first nanofiltration water inlet pump 112 and a second nanofiltration water inlet pump 122, the security filters include a first security filter 114 and a second security filter 124, the nanofiltration high pressure pump includes a first nanofiltration high pressure pump 116 and a second nanofiltration high pressure pump 126, the nanofiltration membranes comprise a first nanofiltration membrane 118 and a second nanofiltration membrane 128, the first nanofiltration water inlet pump 112, the first safety filter 114, the first nanofiltration high-pressure pump 116, the first nanofiltration membrane 118, the second nanofiltration water inlet pump 122, the second safety filter 124, the second nanofiltration high-pressure pump 126 and the second nanofiltration membrane 128 are connected in sequence, the first nanofiltration membrane 118 and the second nanofiltration membrane 128 are respectively connected with the nanofiltration water production tank 220, the first nanofiltration membrane 118 and the second nanofiltration membrane 128 are connected to the nanofiltration concentrate tank 320, respectively.
In some embodiments, a cleaning water tank 900 is included, and the cleaning water tank 900 is connected to the nanofiltration membrane for washing the nanofiltration membrane.
In the liquid evaporation process in the sodium chloride evaporation crystallization system 210, sodium chloride is crystallized and separated out, a very small amount of high-valence sodium salt is continuously enriched, and meanwhile, a small amount of impurities such as organic matters and the like are continuously enriched along with the concentration of wastewater, and are finally discharged in the form of sodium chloride evaporation mother liquor. In the mother liquor, the main components are sodium chloride, sodium sulfate, nitrate and COD. In one embodiment, the temperature of the evaporative crystallization system 210 for evaporative crystallization is 75-102 ℃.
In a similar way, in the liquid evaporation process of the sodium sulfate evaporation freezing crystallization system 310, sodium sulfate is crystallized and separated out, sodium sulfate and sodium chloride mixed salt is continuously separated out through evaporation crystallization, few monovalent sodium salt is enriched, meanwhile, a small amount of impurities such as nitrate, COD (chemical oxygen demand) and the like are continuously enriched along with the concentration of wastewater, and finally, the sodium sulfate evaporation mother liquor is discharged in a form of sodium sulfate evaporation mother liquor. In one embodiment, the temperature for evaporative crystallization in the sodium sulfate salt evaporative crystallization system is 75-102 ℃.
The reverse osmosis membrane 230 applies pressure to the high-salinity wastewater on one side of the reverse osmosis membrane 230, when the pressure exceeds the osmotic pressure of the high-salinity wastewater, the solvent can perform reverse osmosis in the direction opposite to the natural osmosis direction, the separation of salt ions and water in the high-salinity wastewater is realized, the solvent is separated from the high-salinity wastewater, and the concentrated produced water and the concentrated water are obtained. In some embodiments, a reverse osmosis membrane 230 is disposed between the nanofiltration water production tank 220 and the sodium chloride evaporative crystallization system 210. The reverse osmosis membrane 230 is mainly used for concentrating salt, realizing the separation of salt and water and reducing the system scale.
The organic matter treatment system can comprise a system for carrying out ozone contact oxidation, and can also comprise other treatment processes capable of improving COD biodegradability, such as any one or more of an electrolytic treatment process system, a Fenton treatment process system and the like.
The biochemical treatment system can comprise any one or more of treatment process systems for removing nitrate, nitrite and ammonia, such as an electrocatalytic treatment process, a nitrification and denitrification process and the like.
In some embodiments, the ratio of the mass of ozone added in the step of ozone contact oxidation treatment to the total mass of COD in the sodium chloride evaporation mother liquor and part of the sodium sulfate evaporation mother liquor is O3：COD＝(0.8～1.2):1。
In some embodiments, the ozone contact oxidation system can include a dissolved gas device, a gas-liquid mixer, an ozone generator, a reaction tank, or a reaction tower.
Denitrifying bacteria in biochemical processing system 600 will Nitrate (NO)3-) Reducing nitrogen (N) in (C) to nitrogen (N)2) BOD in wastewater5the/TN value is more than 3-5, a carbon source is provided for denitrifying bacteria, the optimal pH value range is 6.5-7.5, the denitrification rate is highest, the optimal growth temperature of denitrifying bacteria is 20-40 ℃, and the denitrification rate is obviously reduced when the temperature is lower than 15 ℃. The denitrifying bacteria can not only convert nitrate into nitrogen, but also reduce COD as a carbon source to below 200 mg/L. In some embodiments, the method further comprises the step of adjusting the pH value of the diluted evaporation mother liquor to 6.5-7.5 before biochemical treatment. In some embodiments, the temperature of the biochemical treatment is between 10 ℃ and 40 ℃.
In order to verify the treatment effect of the high-salinity industrial wastewater treatment method and system provided by the invention on the high-salinity industrial wastewater, a high-salinity industrial wastewater treatment project of a coal-to-olefin project is taken as an example and is explained with reference to fig. 2.
The wastewater water quantity Q: 10m3/h，COD：65mg/L，TDS：11800mg/L，Cl-：3165mg/L，SO4 2-: 3800mg/L, Total hardness: 850mg/L, silica: 47mg/L, turbidity: 3 NTU.
(1) The water quality index of the industrial wastewater with high salt content entering the nanofiltration system after the industrial wastewater with high salt content to be treated is subjected to front-end pretreatment, primary membrane concentration and ion exchange resin is as follows：TDS＝55000mg/L，Cl-＝15200mg/L，SO4 2-18500mg/L, total hardness 0.5mg/L, COD 315mg/L, pH 7.5, and flow rate Q2.1 m3/h。
The pretreatment of the front end of the case adopts a high-density sedimentation tank and an ultrafiltration device, incoming water is sent into the high-density sedimentation tank by a centrifugal pump, PFS, sodium carbonate, sodium hydroxide and PAM medicaments are added by a metering pump under the frequency conversion control in sequence, the pH value of the incoming water is controlled to be 10-10.5, suspended matters and calcium and magnesium hardness in the incoming water are removed, and the pH value of the produced water is adjusted to be 7-7.5 by adding sulfuric acid under the frequency conversion control of the metering pump; a sludge reflux pump and a sludge discharge pump are arranged to adjust and control the sedimentation effect;
the primary membrane concentration device adopts a single-stage two-section combined 8-inch sea fresh membrane element, consists of the 8-inch sea fresh membrane element and a membrane shell, the centrifugal pump is used as a water inlet pump, the vertical multistage centrifugal pump is driven by frequency conversion and used as a booster pump, and the recovery rate of the common regulating valve regulating device is high. The device produced water is sent into a total water production pipe, and the device concentrated water is sent into a device concentrated water tank;
after the concentrated water of the primary concentration device is homogenized and regulated by a concentrated water tank, the concentrated water is sent into ion exchange resin by a centrifugal pump. The ion exchange resin adopts a lower inlet and upper outlet mode, and the hardness of calcium and magnesium in the water is removed by layered adsorption of common sodium type + chelating resin.
The nanofiltration system adopts a two-stage two-section combined nanofiltration membrane element, wherein the first-stage concentrated water and the second-stage concentrated water are converged and used as two-stage inlet water, the first-stage produced water and the second-stage produced water are converged and used as two-stage inlet water, the second-stage produced water is combined nanofiltration final produced water, and the second-stage concentrated water is combined nanofiltration final concentrated water.
(2) The nanofiltration system separates the industrial wastewater with high salt content to be treated into nanofiltration product water and nanofiltration concentrated water.
TDS (total dissolved solids) of nanofiltration produced water is 30500mg/L, total hardness is 0mg/L, and Cl is added-＝19800mg/L，SO4 2-52mg/L, 125mg/L COD, 1560L/h of water produced by the first-stage nanofiltration and 1410L/h of water produced by the second-stage nanofiltration. TDS (total dissolved solids) of nanofiltration concentrated water is 80700mg/L, total hardness is 2.55mg/L, and SO is4 2-＝54000mg/L，Cl-9800mg/L, COD 795mg/L, concentrated water flow rate of first stage nanofiltration 520L/h, and second stage nanofiltrationThe concentrated water flow is 150L/h.
The final water produced by the nanofiltration system and the final concentrated water enter the nanofiltration water production tank 220 and the nanofiltration concentrated water tank 320 respectively for homogenization and adjustment.
(3) The nanofiltration produced water enters a DTRO device (reverse osmosis membrane 230) for deep concentration, the TDS of the DTRO concentrated water is 100050mg/L, and the DTRO concentrated water enters a sodium chloride evaporative crystallization system 210 to produce sodium chloride crystal salt.
The DTRO device adopts single-stage and single-section combination, consists of four membrane columns, is driven by a three-plunger pump in a variable frequency mode, and ensures that the TDS value on the concentrated water side of the device is stable due to the recovery rate of an electric needle valve adjusting device.
The sodium chloride evaporative crystallization system 210 adopts triple effect evaporation, the evaporative concentrate enters an enamel kettle vacuum pump to pump negative pressure to continue evaporative concentration, 40% of solid-to-liquid ratio is reached, and the evaporative concentrate enters a centrifuge to produce sodium chloride crystal salt.
(4) Nanofiltration concentrated water Cl-1Ions and SO4 2-The ion concentration ratio is about 1:5.5, COD is 795mg/L, and the sodium sulfate crystal salt is obtained by entering a sodium sulfate evaporation and freezing crystallization system 310 and carrying out evaporation crystallization at the temperature of about 105 ℃.
The sodium sulfate evaporation freezing crystallization system 310 adopts single-effect evaporation, the evaporation concentrated solution enters an enamel kettle and is pumped by a vacuum pump to continue evaporation concentration under negative pressure, 40% of solid-liquid ratio is reached, and the evaporation concentrated solution enters a centrifuge to produce sodium sulfate crystallized salt.
(5) The purity of the produced sodium chloride crystal salt is 99.7 percent, and meets the first-grade standard of refined industrial salt in the Industrial salt (GB/T5462-2015);
the purity of the produced sodium sulfate crystal salt is 98.7 percent, and the sodium sulfate crystal salt meets the standard of class II first-class products of Industrial anhydrous sodium sulfate (GB/T6009-2014).
(6) And continuously evaporating partial evaporation mother liquor of the sodium sulfate evaporation freezing crystallization system 310 to obtain mixed salt with main components of sodium sulfate and sodium chloride, and dissolving the mixed salt in the dissolving tank 800 through the total product water of the system and then entering the nanofiltration system again to circularly separate the salt.
The sodium sulfate and sodium chloride mixed salt is sent into the dissolving tank 800 by a belt conveyer, dissolved by the total reverse osmosis water production, and the salt concentration of the solution is controlled by detecting the concentration value of the sodium sulfate of the solution and controlling the total reverse osmosis water production entering the dissolving tank 800. The concentration of sodium sulfate of the salt solution is controlled to be basically consistent with that of the sodium sulfate of the water solution entering the nanofiltration device so as to ensure the stability of the driving pressure.
And the dissolved mixed salt solution enters a nanofiltration water inlet tank, is homogenized with the incoming water, and then enters a nanofiltration device for circulating salt separation.
(7) The mother liquor discharged from the sodium sulfate evaporative freezing crystallization system 310 and the mother liquor discharged from the sodium chloride evaporative crystallization system 210 are homogenized and then enter the organic matter treatment system 400, the biodegradability of the mother liquor is improved through ozone contact oxidation treatment, and the mother liquor is diluted by total system production water and then enters the biochemical treatment system 600 for denitrification treatment.
In the case, a column type organic matter treatment system 400 with a lower inlet and an upper outlet is adopted, the ozone adding amount is controlled by adjusting and controlling the ratio of ozone to organic matters in the mother liquor, the ozone adding ratio is controlled to be 1:1, and a certain amount of sodium hydroxide tablets are added to control the pH value of the mother liquor to be kept in a range of 9-10.5 all the time in the reaction process.
(8) The water quality indexes of the discharged mother liquor which enters the biochemical treatment system 600 after being diluted by the total reverse osmosis produced water are as follows: TDS (total dissolved solids) ═ 10200mg/L, NO3 -1010mg/L, total hardness 3.5mg/L, COD 430mg/L, pH 7.5, and flow rate Q1.5 m3H; controlling the carbon-nitrogen ratio, and treating by the biochemical denitrification system 600, wherein the water quality indexes of the biochemical produced water are as follows: TDS 10000mg/L, NO3 -65mg/L, 3.5mg/L total hardness, 55mg/L COD, 7.5 pH, and 1.5m Q flow3/h；
The organic matter treatment system 400 produces water that is sent into the dilution tank 500 by the centrifugal pump, is diluted through the total produced reverse osmosis water, controls the total produced reverse osmosis water volume that enters the dissolving tank 800 through detecting the TDS value of the diluted salt solution to control the salt concentration of the solution. The TDS value of the saline solution after the dilution is controlled to be basically consistent with the TDS value of the saline solution entering the pretreatment device.
The diluted salt solution is sent into a biochemical treatment system 600 by a centrifugal pump after being homogenized and regulated, nutrient substances are added to ensure the carbon-nitrogen ratio of the solution, and biological bacteria denitrification is carried out to remove nitrate radicals in the salt solution. The case is provided with a heat exchanger to provide proper environmental temperature for the biological bacteria so as to ensure the normal operation of the biochemical denitrification.
The salt solution after biochemical treatment is sent into a pretreatment regulating tank by a centrifugal pump, is homogenized and regulated with incoming water, then enters a pretreatment system, and then enters a nanofiltration system for circulating salt separation.
After 72 hours of continuous operation, the treated water quantity is 710m32.3 tons of sodium chloride crystal salt and 3.8 tons of sodium sulfate crystal salt are obtained, no evaporation mother liquor is discharged, and zero discharge of the evaporation mother liquor is realized.
(9) The nanofiltration membrane is chemically cleaned after continuously running for 180 days, and meanwhile, the nanofiltration membrane is replaced, so that the normal running of a nanofiltration system during the cleaning period of the nanofiltration membrane is ensured. In the cleaning process, 0.3 percent NaOH and 2 percent EDTA solution are adopted in the cleaning water tank 900 to be washed for 8 hours under the condition of low pressure, and then the produced water is used for washing for 30 minutes, so that the original performance of the nanofiltration membrane is recovered.
Comparative example
The comparative example is different from the above embodiment in that the organic matter treatment system 400, the dilution tank 500 and the biochemical treatment system 600 are not provided to remove COD and nitrate in the evaporation mother liquor, and the mixed salt is not dissolved and refluxed to the nanofiltration system: after 72 hours of continuous operation, the treated water quantity is 520m3To obtain 1.3 tons of sodium chloride crystal salt and 2.5 tons of sodium sulfate crystal salt, and discharging 12.7m of evaporated mother liquor3The ozone addition was increased by 1.5 times.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The method for treating the evaporation mother liquor of the high-salt-content wastewater is characterized by comprising the following steps of:
carrying out nanofiltration treatment on the high-salt-content wastewater after pretreatment, carrying out evaporative crystallization treatment on filtrate to separate out sodium chloride product salt to obtain sodium chloride evaporative mother liquor, evaporating and concentrating trapped fluid, and carrying out freezing crystallization treatment to separate out mirabilite to obtain sodium sulfate frozen mother liquor;
continuously evaporating and crystallizing the sodium sulfate freezing mother liquor to separate out sodium sulfate and sodium chloride mixed salt to obtain sodium sulfate evaporating mother liquor, dissolving and diluting the mixed salt, and refluxing to a nanofiltration system;
and sequentially carrying out organic matter treatment, dilution and biochemical treatment on the sodium chloride evaporation mother liquor and the sodium sulfate evaporation mother liquor, then refluxing to a pretreatment system, and then entering a nanofiltration system for nanofiltration treatment.
2. The method for treating the evaporation mother liquor of wastewater with high salt content as claimed in claim 1, wherein the step of treating the organic matters is to perform ozone contact oxidation, and the ratio of the mass of the added ozone to the total mass of COD in the evaporation mother liquor of sodium chloride and the evaporation mother liquor of sodium sulfate is O3：COD＝(0.8～1.2):1。
3. The method for treating the evaporation mother liquor of the high-salinity wastewater as claimed in claim 1, further comprising the step of adjusting the pH value of the diluted evaporation mother liquor to 6.5-7.5 before biochemical treatment.
4. The method for treating the evaporation mother liquor of the wastewater with high salt content according to claim 1, wherein the temperature of the biochemical treatment is 10-40 ℃.
5. A high salt waste water evaporation mother liquor treatment system of a treatment method of high salt waste water is characterized by comprising the following steps:
the nanofiltration system is used for separating sodium chloride and sodium sulfate in the high-salt-content wastewater;
the sodium chloride evaporation crystallization system is provided with a sodium chloride concentrated water inlet and a sodium chloride evaporation mother liquor outlet which are communicated with a sodium chloride water outlet of the nanofiltration system;
the sodium sulfate evaporation and freezing crystallization system is provided with a sodium sulfate concentrated water inlet and a sodium sulfate evaporation mother liquor outlet which are communicated with a sodium sulfate water outlet of the nanofiltration system;
the device comprises an organic matter treatment system, a dilution tank and a biochemical treatment system which are sequentially communicated, wherein the nanofiltration system, the sodium chloride evaporative crystallization system, the organic matter treatment system, the dilution tank and the biochemical treatment system form a first closed loop, and the nanofiltration system, the sodium sulfate evaporative freezing crystallization system, the organic matter treatment system, the dilution tank and the biochemical treatment system form a second closed loop;
the nanofiltration system, the sodium sulfate evaporation freezing crystallization system and the dissolving tank form a third closed loop.
6. The high salinity wastewater evaporation mother liquor processing system of claim 5, wherein, the nanofiltration system comprises a nanofiltration water inlet pump, a cartridge filter, a nanofiltration high-pressure pump and a nanofiltration membrane which are connected in sequence.
7. The high salinity wastewater evaporation mother liquor processing system of claim 6, further comprising a nanofiltration water production tank and a nanofiltration concentrated water tank respectively connected with the nanofiltration membrane, wherein the nanofiltration water production tank is connected with the sodium chloride evaporative crystallization system, and the nanofiltration concentrated water tank is connected with the sodium sulfate evaporative freezing crystallization system.
8. The evaporation mother liquor treatment system for high salinity wastewater according to claim 7, the nanofiltration water inlet pump comprises a first nanofiltration water inlet pump and a second nanofiltration water inlet pump, the security filter comprises a first security filter and a second security filter, the nanofiltration high-pressure pump comprises a first nanofiltration high-pressure pump and a second nanofiltration high-pressure pump, the nanofiltration membranes comprise a first nanofiltration membrane and a second nanofiltration membrane, the first nanofiltration water inlet pump, the first safety filter, the first nanofiltration high-pressure pump, the first nanofiltration membrane, the second nanofiltration water inlet pump, the second safety filter, the second nanofiltration high-pressure pump and the second nanofiltration membrane are connected in sequence, the first nanofiltration membrane and the second nanofiltration membrane are respectively connected with the nanofiltration water production tank, and the first nanofiltration membrane and the second nanofiltration membrane are respectively connected with the nanofiltration concentrated water tank.
9. The evaporation mother liquor treatment system for high-salinity wastewater according to claim 5, characterized by comprising a washing water tank, wherein the washing water tank is connected with the nanofiltration membrane.
10. The high salinity wastewater evaporation mother liquor processing system of claim 7, characterized in that, be provided with reverse osmosis membrane between nanofiltration water production jar and the sodium chloride evaporation crystallization system.
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| CN117923704A (en) * | 2024-01-18 | 2024-04-26 | 广东台泉科技股份有限公司 | Resource utilization method of shale oil high-salinity wastewater |
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