Summary of the invention
In view of defect present in above-mentioned saliferous wastewater processing technology, it is useless that an object of the present invention is to provide a kind of saliferousAll kinds of salt in brine waste can pointedly be recycled, it is attached to obtain available high quality by the salt recovery system of waterAdd product.
It is a further object of the present invention to provide a kind of salt recovery methods of brine waste.
It is a further object of the present invention to provide a kind of processing system of brine waste and processing methods.
The salt recovery system of brine waste provided by the invention, for containing to resulting after the brine waste desalting processingThe-salt concentrated water progress salt recycling of sodium chloride, sodium sulphate, sodium nitrate comprising following processing unit:
First nano-filtration unit, to carry out nanofiltration processing to the-salt concentrated water；
Ozone oxidation unit is connected with first nano-filtration unit, to the nanofiltration retention to first nano-filtration unitLiquid carries out ozone Oxidation Treatment；
Chelating resin absorbing unit is connected with the ozone oxidation unit, to the water outlet to the ozone oxidation unitCarry out adsorption treatment；
Sodium sulphate freezing and crystallizing unit is connected with the chelating resin absorbing unit and first nano-filtration unit respectively,Freeze crystallization is carried out to the water outlet to the chelating resin absorbing unit and recycles sodium sulfate crystal, while water outlet being returnedTo first nano-filtration unit；
Sodium chloride evaporative crystallization unit is connected with first nano-filtration unit, to receive to first nano-filtration unitFilter permeate is evaporated crystallization treatment, recycling sodium chloride crystal while outlet mother liquor；
Sodium nitrate freezing and crystallizing unit is connected with the sodium chloride evaporative crystallization unit, to evaporate to the sodium chlorideThe outlet mother liquor of crystalline element carries out Freeze crystallization and recycles nitric acid sodium crystal；And
Second nano-filtration unit, respectively with the sodium nitrate freezing and crystallizing unit, the ozone oxidation unit and the chlorinationSodium evaporative crystallization unit is connected, and carries out nanofiltration processing, nanofiltration retentate fluid to the water outlet to the sodium nitrate freezing and crystallizing unitIt is back to the ozone oxidation unit, nanofiltration membrane permeate is back to the sodium chloride evaporative crystallization unit.
In the salt recovery system of brine waste provided by the invention, the ozone oxidation unit includes 2~5 grades concatenatedOzone oxidation generator.
In the salt recovery system of brine waste provided by the invention, the ratio of height to diameter of the ozone oxidation generator is 5~15；Preferably 8~12.
The present invention also provides a kind of processing systems of brine waste comprising following system:
Desalination system obtains producing water and sodium chloride-containing, sulfuric acid to carry out desalting processing to brine waste to be processedThe-salt concentrated water of sodium, sodium nitrate；
Salt recovery system is that above technical scheme is described in any item to carry out salt recycling containing concentrated water to describedSalt recovery system.
In the processing system of brine waste provided by the invention, the desalination system successively includes connected following processing listMember:
Clarify pliable cell, to brine waste to be processed add medicament clarified, sofening treatment；
First medium filter element is filtered processing to the water outlet to the clarification pliable cell；
Membrane filter unit carries out film filtration treatment to the water outlet to the first medium filter element；
Resin cation pliable cell is carried out to the water outlet to the membrane filter unit by cation exchange resin softChange processing；
Removing carbon dioxide unit, to carry out CO in the water outlet to the resin cation pliable cell2Removing processing；
Preposition reverse osmosis units carry out reverse osmosis deaslination processing to the water outlet to the removing carbon dioxide unit；
Second medium filter element is filtered processing to the reverse osmosis concentrated water to the preposition reverse osmosis units；WithAnd
Reverse osmosis units carry out reverse osmosis deaslination processing to the water outlet to the second medium filter element, and gained is anti-Infiltration concentrated water is sodium chloride-containing, the-salt concentrated water of sodium sulphate, sodium nitrate.
In the processing system of brine waste provided by the invention, the chelating resin absorbing unit in the salt recovery system is alsoIt is connected with the clarification pliable cell in the desalination system.
The present invention also provides a kind of salt recovery methods of brine waste, for institute after the brine waste desalting processingThe-salt concentrated water progress salt recycling of the sodium chloride-containing, sodium sulphate, sodium nitrate that obtain comprising following processing step:
The-salt concentrated water is carried out nanofiltration processing by the first nano-filtration step；
Ozone oxidation step, the nanofiltration retentate fluid that first nano-filtration step is generated carry out ozone Oxidation Treatment；
The water outlet of the ozone oxidation step is carried out adsorption treatment by chelating resin adsorption step；
The water outlet of the chelating resin adsorption step is carried out Freeze crystallization and recycles sulphur by sodium sulphate freezing and crystallizing stepSour sodium crystal, while water outlet is back to first nano-filtration step；
The nanofiltration permeate liquid that first nano-filtration step generates is evaporated at crystallization by sodium chloride evaporative crystallization stepsReason, recycling sodium chloride crystal while outlet mother liquor；
The outlet mother liquor of the sodium chloride evaporative crystallization steps is carried out Freeze crystallization by sodium nitrate freezing and crystallizing stepRecycle nitric acid sodium crystal；And
The water outlet of the sodium nitrate freezing and crystallizing step is carried out nanofiltration processing, and nanofiltration is retained by the second nano-filtration stepLiquid is back to the ozone oxidation step and is handled, and nanofiltration membrane permeate is back to the sodium chloride evaporative crystallization steps and carries outProcessing.
In the salt recovery method of brine waste provided by the invention, in the ozone oxidation step, O3Dosage is described1~5 times of COD total amount in nanofiltration retentate fluid, catalytic oxidation time are 60~300 minutes.
In the salt recovery method of brine waste provided by the invention, in the outlet mother liquor of the sodium chloride evaporative crystallization stepsThe concentration of sodium nitrate is 700~1800g/L, preferably 800~1500g/L.
In the salt recovery method of brine waste provided by the invention, the sodium nitrate freezing and crystallizing step further include: to instituteIt states and demineralized water is added in the outlet mother liquor of sodium chloride evaporative crystallization steps to dilute the outlet mother liquor, the additional amount of demineralized water isThe 5~100% of the outlet mother liquor volume.
The present invention also provides a kind of processing methods of brine waste comprising following steps:
S1: desalting processing is carried out to brine waste to be processed, recycling produces water and obtains sodium chloride-containing, sodium sulphate, nitric acidThe-salt concentrated water of sodium；
S2: salt is carried out using above technical scheme described in any item salt recovery methods to the resulting-salt concentrated water of step S1Recycling.
In the processing method of brine waste provided by the invention, the desalting processing successively includes following processing step:
Clarify bating step, to brine waste to be processed add medicament clarified, sofening treatment；
First medium filtration step is filtered processing to the water outlet of the clarification bating step；
The water outlet of the first medium filtration step is carried out film filtration treatment by membrane filtration step；
Resin cation bating step carries out the water outlet of the membrane filtration step at softening by cation exchange resinReason；
The water outlet of the resin cation bating step is carried out CO by removing carbon dioxide step2Removing processing；
The water outlet of the removing carbon dioxide step is carried out reverse osmosis deaslination processing by preposition reverse osmosis step；
Second medium filtration step is filtered processing to the reverse osmosis concentrated water of the preposition reverse osmosis step；And
The water outlet of the second medium filtration step is carried out reverse osmosis deaslination processing by reverse osmosis step, and gained is reverse osmosisConcentrated water is sodium chloride-containing, the-salt concentrated water of sodium sulphate, sodium nitrate.
System and method provided by the invention can effectively recycle solid sodium chloride, the nitric acid of high-purity from brine wasteThe products such as sodium, saltcake will not generate unserviceable mixed salt, realize the recycling treatment of brine waste, organic in waste waterObject etc. can also be handled, and without secondary pollution, thus be truly realized the zero-emission of brine waste.Moreover, the present invention is alsoThe fouling and dirty stifled tendency of the devices such as nanofiltration can be effectively relieved, thus can guarantee that salt recovery system, waste water treatment system are long-term, steadyDetermine, reliably run.
Specific embodiment
To make the object, technical solutions and advantages of the present invention clearer, it is described more fully with and shows with reference to the drawingsExample embodiment.However, example embodiment can be implemented in a variety of forms, and it is not understood as limited to reality set forth hereinApply mode；On the contrary, thesing embodiments are provided so that the present invention will be full and complete, and the design of example embodiment is comprehensiveGround is communicated to those skilled in the art.Identical appended drawing reference indicates same or similar structure in figure, thus will omit itDetailed description.
The first aspect of the invention provides a kind of salt recovery system of brine waste, can be used for brine waste desalinationThe-salt concentrated water progress salt recycling of resulting sodium chloride-containing, sodium sulphate, sodium nitrate after processing comprising following processing unit, such asShown in Fig. 1.
First nano-filtration unit 9, to carry out nanofiltration processing to-salt concentrated water to be recycled；
Ozone oxidation unit 11 is connected with the first nano-filtration unit 9, to the nanofiltration retentate fluid to the first nano-filtration unit 9 intoRow ozone Oxidation Treatment；
Chelating resin absorbing unit 12 is connected with ozone oxidation unit 11, to the water outlet to ozone oxidation unit 11 intoRow adsorption treatment；
Sodium sulphate freezing and crystallizing unit 13 is connected with chelating resin absorbing unit 12 and the first nano-filtration unit 9 respectively, toFreeze crystallization is carried out to the water outlet of chelating resin absorbing unit 12 and recycles sodium sulfate crystal, while water outlet is back to firstNano-filtration unit 9；
Sodium chloride evaporative crystallization unit 10 is connected with the first nano-filtration unit 9, saturating to the nanofiltration to the first nano-filtration unit 9It crosses liquid and is evaporated crystallization treatment, recycling sodium chloride crystal while outlet mother liquor；
Sodium nitrate freezing and crystallizing unit 14 is connected, to sodium chloride evaporative crystallization with sodium chloride evaporative crystallization unit 10The outlet mother liquor of unit 10 carries out Freeze crystallization and recycles nitric acid sodium crystal；And
Second nano-filtration unit 15 is evaporated with sodium nitrate freezing and crystallizing unit 14, ozone oxidation unit 11 and sodium chloride respectivelyCrystalline element 10 is connected, and carries out nanofiltration processing to the water outlet to sodium nitrate freezing and crystallizing unit 14, nanofiltration retentate fluid is back toOzone oxidation unit 11, nanofiltration membrane permeate are back to sodium chloride evaporative crystallization unit 10.
Specifically, brine waste obtained after desalting processing sodium chloride-containing, sodium sulphate, sodium nitrate-salt concentrated water I, it is firstIt is introduced into the first nano-filtration unit 9, the first nano-filtration unit 9 is provided with nanofiltration membrane component, and sodium chloride, sodium nitrate and water energy penetrate nanofiltrationFilm and most of organic matter and SO42-Nanofiltration membrane cannot be penetrated, therefore ,-salt concentrated water I is divided into two streams by nanofiltration membrane component,I.e. rich in sodium chloride, the first nanofiltration permeate liquid K of sodium nitrate and rich in organic matter and SO42-The first nanofiltration retentate fluid J.TheIn one nanofiltration permeate liquid K, other impurities are eliminated, contain a large amount of NaCl and a small amount of NaNO3, KCl, into sodium chloride evaporateCrystalline element 10, the first nanofiltration retentate fluid J then enter ozone oxidation unit 11.
The present invention does not have special restriction to nanofiltration membrane component, and the common nanofiltration membrane component in this field can be used.At oneIn preferred embodiment, it can be selected to organic matter and SO42-The high nanofiltration membrane component of removal rate.In a preferred embodiment,The inflow temperature of nanofiltration membrane can be 5~40 DEG C, further preferably can be 10~35 DEG C, still further preferably can for 20~25 DEG C, so as to by SO in the first nanofiltration permeate liquid K42-Concentration be concentrated to ideal numerical value as far as possible without being saturated.ForIn subsequent sulphuric acid sodium freezing and crystallizing unit 13 more sodium sulphate are isolated with energy consumption needed for saving freezing, need to make SO42-Concentration improves as far as possible, is preferably concentrated 3~10 times, 5~8 times is further preferably concentrated, it is possible thereby to make the first nano-filtration unit 9The first nanofiltration retentate fluid J in SO42-Concentration reach 13.6~488g/L, preferably reach 20~110g/L, further preferably reachTo 100~110g/L.
First nanofiltration retentate fluid J of the first nano-filtration unit 9 enters ozone oxidation unit 11, and ozone oxidation unit 11 is provided withOzone oxidation reaction device.After first nanofiltration retentate fluid J is freezed in subsequent sodium sulphate freezing and crystallizing unit 13, one thereinSulfate crystal is divided to come out, the influent side that remaining water outlet returns to the first nano-filtration unit 9 continues to carry out sodium sulphate therein denseDivision from.If not being removed to organic matter will gradually be enriched in nanofiltration retentate fluid, once the excessively high meeting of organic concentrationEndanger the operation of nanofiltration membrane component.Therefore, the first nanofiltration retentate fluid J initially enters ozone oxidation unit 11 and is handled, toOzone (O is passed through in one nanofiltration retentate fluid J3) Q, organic matter therein is finally oxidized to CO2And water.
O3Oxygenolysis organic matter needs certain residence time, especially O3It is slower with the reaction of aromatic compound, andIn brine waste (especially coal chemical industrial waste water), wherein the content of aromatic compound is higher after being concentrated step by step, therefore, isIt obtains higher oxidation operation discomposing effect, needs to guarantee enough O3Dosage and oxidation time of contact.Of the inventionOzone oxidation unit 11 is arranged after nano-filtration unit salt recovery system, has added O3Brine waste afterwards can also undergo sulfuric acidSodium freezing and crystallizing, chelating resin adsorb two processing units, and residual ozone also can proceed with decomposition during this period, thus can guaranteeWaste water removes ozone before returning to nano-filtration unit as thoroughly as possible, and ozone is avoided to cause damages nanofiltration membrane component.
In a preferred embodiment, the dosage of ozone Q can be organic in 1~5 times of first nanofiltration retentate fluid JThe COD total amount of object, oxidation time of contact preferably can be 30~500 minutes, further preferably can be 60~360 minutes, mostIt is preferred that can be 180~300 minutes.The present invention has no special restriction for selected ozone oxidation reaction device, can adopt, preferably can be hybrid for Gas-liquid pump with ozone-oxidizing device commonly used in the art, to provide higher O3Dissolved efficiency, into oneStep is preferably using oxygen as the ozone generator of gas source, because can provide higher ozone by the ozone generator of gas source of oxygenConcentration, higher ozone concentration are conducive to the oxygenolysis of organic matter.
Since salt content is very high in the first nanofiltration retentate fluid J, in high-salt wastewater, the dissolution of ozone and mass transfer are all more tiredDifficulty, in order to improve treatment effect, plural serial stage form is can be used in ozone oxidation reaction device, for example, can be two to Pyatyi, preferablyIt can be thtee-stage shiplock.Meanwhile higher ratio of height to diameter also can be used in ozone oxidation reaction device, preferably ratio of height to diameter can be 5~15,It further preferably can be 8~12, to further increase the utilization efficiency of ozone Q.
The water outlet of ozone oxidation unit 11 enters chelating resin absorbing unit 12, and chelating resin absorbing unit 12 is using chelating treeRouge adsorbs the polyvalent cation in water, to prevent hardness and heavy metal ion to be gradually enriched in nanofiltration retentate fluid.Chelating resinAdsorption capacity is stronger under the conditions of higher ph, hardness remaining in waste water can be reduced to 100ppb hereinafter, and waste waterIn high salinity will not have any impact to its adsorption capacity.In a preferred embodiment, chelating resin absorption is singleThe chelating bed that member 12 can use this field common.
The water outlet of chelating resin absorbing unit 12 enters sodium sulphate freezing and crystallizing unit 13, and sodium sulphate freezing and crystallizing unit 13 wrapsContaining freezing and crystallizing separator, chelating resin absorbing unit 12 is discharged by frozen cooling by external cooling medium, with temperatureThe reduction of degree, the sodium sulphate dissolved in water reaches hypersaturated state and is precipitated in crystalline form, and separates from solution.SolutionIn NaCl still exist in the form of a solution, will not be precipitated, to obtain the very high sodium sulphate product of purity.Cryogenic temperature canThink -5~25 DEG C, preferably can be -5~10 DEG C, further preferably can be -5~5 DEG C, it can the purpose is to use up sodium sulphateIt can mostly crystallize out from solution and reduce freezing cost.The water outlet of sodium sulphate freezing and crystallizing unit 13 is received back to firstFilter unit 9 continues with.
First nanofiltration permeate liquid K of the first nano-filtration unit 9 enters sodium chloride evaporative crystallization unit 10, sodium chloride evaporative crystallizationCrystallizing evaporator is provided in unit 10.It is heated in crystallizing evaporator using steam, makes the moisture in the first nanofiltration permeate liquid KEvaporation, with continuing for evaporation, Chlorine in Solution na concn is continuously improved, and is analysed in crystalline form until reaching hypersaturated stateOut, and from solution it separates, obtains solid sodium chloride product M, resulting sodium chloride purity is higher (up to 99% or more),Industrial grade standard can be reached.The gas of evaporation is condensed into evaporation lime set S and recycles.The present invention is for sodium chloride evaporative crystallizationThere is no special restrictions for device, such as can use multiple-effect evaporation well known in the art or MVR evaporative crystallization.
In first nanofiltration permeate liquid K in addition to the sodium chloride containing high concentration, also contain a small amount of sodium nitrate and sodium sulphate, withAnd the sylvite of these lesser amount of anion, in sodium chloride evaporation and crystal process, also gradually concentration increases the concentration of these salt,Precipitation can be also crystallized after reaching saturated concentration, the crystallization of these salt is precipitated and influences the product quality of sodium chloride in order to prevent,Therefore periodically interruption or continuous outlet is needed to evaporate mother liquor L on a small quantity, to control the concentration range of sodium nitrate in evaporation mother liquor as 700~1800g/L, preferably 800~1500g/L.
The evaporation mother liquor L discharged from sodium chloride evaporative crystallization unit 10 enters sodium nitrate freezing and crystallizing unit 14, adds simultaneouslyA small amount of demineralized water N is added to dilute, the additive amount of demineralized water can be the 5~100% of evaporation mother liquor L volume.Sodium nitrate freezing and crystallizingUnit 14 includes freezing and crystallizing separator, the evaporation for being discharged sodium chloride evaporative crystallization unit 10 by external cooling mediumMother liquor L frozen cooling evaporates the sodium nitrate dissolved in mother liquor L and reaches hypersaturated state in crystalline form with the reduction of temperatureIt is precipitated, and is separated from solution, resulting sodium nitrate purity is higher (up to 99% or more), can reach technical grade markIt is quasi-.NaCl in solution still exists in the form of a solution, will not be precipitated, and the sodium sulphate in solution is lower also with molten due to concentrationLiquid form exists without being precipitated, to obtain the very high sodium nitrate product P of purity.Cryogenic temperature can be -5~50 DEG C,It is preferred that can be 0~10 DEG C, the purpose is to so that sodium nitrate is crystallized out from solution as much as possible and reduce freezing cost.
Sodium nitrate freezing and crystallizing is discharged O and enters the second nano-filtration unit 15.Second nano-filtration unit 15 is provided with nanofiltration membrane component,Due to sodium chloride, sodium nitrate and water energy through nanofiltration membrane most of organic matter and SO42-Nanofiltration membrane, therefore, nanofiltration cannot be penetratedThe water outlet O of sodium nitrate freezing and crystallizing unit 14 is divided into two streams by membrane module, i.e., second rich in sodium chloride and sodium nitrate receivesIt filters permeate W and is rich in organic matter and SO42-The second nanofiltration retentate fluid T.Second nanofiltration permeate liquid W can return to sodium chloride steamingHair crystalline element 10 continues to recycle sodium chloride and sodium nitrate, and the second nanofiltration retentate fluid T, which is then sent to ozone oxidation unit 11, to be continued backReceive sodium sulphate.
The also not special restriction of the nanofiltration membrane component of second nano-filtration unit 15, can be used the common any nanofiltration in this fieldMembrane module, can also be identical as the nanofiltration membrane component of the first nano-filtration unit 9, so as to by SO in the second nanofiltration retentate fluid T42-'sConcentration is concentrated to ideal numerical value without being saturated as far as possible.
Salt recovery system provided by the invention can be respectively to the sodium chloride, sodium sulphate, sodium nitrate often generated in brine wasteEqual salt carry out targetedly resource utilization.Salt recovery system of the invention can isolated operation, for resulting after desalting processing- salt concentrated water carries out salt recycling, is not limited to the source of-salt concentrated water, as long as wherein containing salt such as sodium chloride, sodium sulphate, sodium nitrate?.The subsystem that salt recovery system of the invention also can be used as salt recycling is used among the treatment process of brine waste.
The second aspect of the invention provides a kind of processing system of brine waste comprising following system:
Desalination system obtains producing water and sodium chloride-containing, sulfuric acid to carry out desalting processing to brine waste to be processedThe-salt concentrated water of sodium, sodium nitrate；
Salt recovery system can be provided to carry out salt recycling containing concentrated water to described for first aspect of the present inventionSalt recovery system.
It in a preferred embodiment, can successively include connected following processing list for desalination system of the inventionMember, as shown in Figure 1.
Clarify pliable cell 1, to brine waste to be processed add medicament clarified, sofening treatment；
First medium filter element 2 is filtered processing to the water outlet to clarification pliable cell 1；
Membrane filter unit 3 carries out film filtration treatment to the water outlet to first medium filter element 2；
Resin cation pliable cell 4 is softened to the water outlet to membrane filter unit 3 by cation exchange resinProcessing；
Removing carbon dioxide unit 5, to carry out CO in the water outlet to resin cation pliable cell 42Removing processing；
Preposition reverse osmosis units 6 carry out reverse osmosis deaslination processing to the water outlet to removing carbon dioxide unit 5；
Second medium filter element 7 is filtered processing to the reverse osmosis concentrated water to preposition reverse osmosis units 6；And
Reverse osmosis units 8 carry out reverse osmosis deaslination processing, gained reverse osmosis to the water outlet to second medium filter element 7Saturating concentrated water is sodium chloride-containing, the-salt concentrated water of sodium sulphate, sodium nitrate.
Clarification pliable cell 1 for add medicament B brine waste A to be processed is clarified, sofening treatment, thus willHardness, suspended matter, amphoteric oxide, colloid and part larger molecular organics in waste water are converted into sludge, and sedimentation removal makes clearClear pliable cell goes out the water hardness less than 100mg/L (with CaCO3Meter), and the basicity in water outlet is made to be greater than hardness.
In a preferred embodiment, the medicament B added is mainly lime or sodium hydroxide softening agent, if there is foreverLong hardness, also optionally adds soda ash, and a small amount of coagulant, wadding are added to being also an option that property while adding softening agentSolidifying agent etc., such as PFS, PAM etc., to promote the aggregation and sedimentation of solid, further, it is also possible to according to waste water quality situation selectivityGround adds other required medicament such as oxidants etc., such as sodium hypochlorite etc..The invention is not limited thereto.
In general, when using NaOH, soda ash softening agent, the reaction equation of softening is as follows:
Ca(HCO3)2+2NaOH→CaCO3↓+Na2CO3+2H2O
Mg(HCO3)2+4NaOH→Mg(OH)2↓+2Na2CO3+2H2O
MgSO4+2NaOH→Mg(OH)2↓+2Na2SO4
MgCl2+2NaOH→Mg(OH)2↓+2NaCl
CO2+2NaOH→Na2CO3+H2O
CaSO4+Na2CO3→CaCO3↓+Na2SO4
CaCl2+Na2CO3→CaCO3↓+2NaCl
When using lime, soda ash softening agent, the reaction equation of softening is as follows:
CO2+Ca(OH)2→CaCO3↓+H2O
Ca(HCO3)2+Ca(OH)2→2CaCO3↓+2H2O
Mg(HCO3)2+Ca(OH)2→CaCO3↓+MgCO3+2H2O
MgCO3+Ca(OH)2→CaCO3↓+Mg(OH)2↓
CaSO4+Na2CO3→CaCO3↓+Na2SO4
CaCl2+Na2CO3→CaCO3↓+2NaCl
MgSO4+Na2CO3→MgCO3+Na2SO4
MgCO3+Ca(OH)2→CaCO3↓+Mg(OH)2
The present invention, can be by those skilled in the art for still using sodium hydroxide softening agent to be not particularly limited using limeMember determines according to the practical water quality situation of brine waste.In general, when being softened using lime can simultaneously with the F in waste water-InsteadCaF precipitating should be generated to slough most of F-, lime softens also more preferable to the removal effect of silicide.Therefore, if saliferousF in waste water-It is higher with the content of Si, then preferred lime softening, but the mud amount that lime softening generates is more.Using sodium hydroxideSoftening can make reaction more thorough and unrelated with medicament addition sequence rapidly, and process flow and equipment are simple, operating costIt is lower with cost of investment, it is easy to accomplish automatic control, the mud amount of generation is small (about reduction half or so), and the consumption of soda ash also comparesIt is small, but settling velocity is slower.
Clarification pliable cell 1 of the invention may include clarification softening pond, softens pond front end in clarification, throws into waste waterAdding medicine softens waste water, and the hardness of wherein most, suspended matter, colloid etc. are converted to solid and are deposited to bottom of pondPortion, while silicide and 25% that can remove 30%~35% or more or more organic matter.The present invention is for clarification softening pondPattern is also not particularly limited, and can soften pond or accelerator using efficient clarification commonly used in the art,It is preferred that softening pond is efficiently clarified, because efficiently the clarification bating effect in clarification softening pond is more preferable, and occupied area only traditionThe part of accelerator.
Clarification pliable cell 1 can also be connected with the chelating resin absorbing unit 12 in salt recovery system, and chelating resin is inhaledThe acid-basic regenerated waste liquids in water R that coupon member 12 generates can return to clarification pliable cell 1 and continue to handle.
Clarify pliable cell 1 treated water outlet enter first medium filter element 2, first medium filter element 2 be arrangedThere is medium filter, be filtered in the presence of one or more filter mediums, so that the suspension content in waste water is further5mg/L is reduced to hereinafter, haze reduction is to 5NTU or less.
The present invention is not particularly limited the form of medium filter, and multimedium mistake commonly used in the art can be usedFilter tank can also can be used using vertical, single layer is horizontal or double-deck horizontal in filter, more medium filter.
The present invention is also not particularly limited the type of filter medium, can be used one or more commonly used in the artFilter medium, such as quartz sand, anthracite etc..In a preferred embodiment, using double media filtrations, filter medium canTo select quartz sand and anthracite, it is further preferred that the granularity of filter medium can be with are as follows: 0.4~0.6mm of quartz sand, smokeless0.8~1.2mm of coal, thickness of filter bed preferably can be with are as follows: quartz sand 800mm, anthracite 400mm, it can also be appropriate according to water quality situationAdjustment.
First medium filter element 2 treated water outlet enter membrane filter unit 3 be filtered processing, film mistake of the inventionFilter unit 3 is provided with filter membrane component, is filtered processing to waste water by the filter membranes such as ultrafiltration membrane, microfiltration membranes component.Pass through film mistakeThe residual suspended matter and colloid in the removable waste water of filtration treatment of unit 3 are filtered, makes the SDI value of waste water less than 3, it is subsequent to meetThe water inlet requirement of reverse osmosis deaslination processing.
Media filtration belongs to traditional in-depth filtration, and film filtering belongs to absolute filtration, and filtering accuracy is high, goes turbid effect moreGood, film filtering and media filtration are used cooperatively, and effluent quality is more preferable, can significantly improve the dirt of colloid in subsequent counter-infiltration systemStifled tendency.In a preferred embodiment, membrane filter unit 3 uses hyperfiltration membrane assembly, and this field can be used in hyperfiltration membrane assemblyIn well known any hyperfiltration membrane assembly, more preferably use external pressure type ultra-filtration membrane component.It is of course also possible to which selecting has same processingThe micro-filtration membrane module of effect.
It is divided into two streams by the waste water that membrane filter unit 3 is handled, i.e., the film filtering containing a small amount of suspended matter and colloidIt is discharged D, and filters concentrated water C rich in the film of suspended matter and colloid.Concentrated water C is again fed to clarification pliable cell 1 after collectingAgain it handles, to improve the utilization rate of water.
Film filtration effluent D enters resin cation pliable cell 4, is filled with cation in resin cation pliable cell 4Exchanger resin, the hardness in waste water are removed by ion exchange, use the water hardness less than 1mg/L (with CaCO3Meter).
In a preferred embodiment, the cation exchange resin loaded in resin cation pliable cell 4 is weak acidCation exchange resin, Weak-acid cation exchange resin are bigger than the exchange capacity of storng-acid cation exchange resin, it is easier to againIt is raw, it can be used in the waste water of high salinity.In a more preferable embodiment, resin cation pliable cell 4 can be adoptedWith weak acid cation bed, ion exchange resin is loaded on wherein.
Sour E is added into treated the water outlet of resin cation pliable cell 4 to adjust the pH value of water outlet to acidity, such asIt can be 4.3 or so, make the CO in waste water32-And HCO3-Ion conversion is at CO2, subsequently into removing carbon dioxide unit 5.Except twoOxidation carbon unit 5 may include a carbon dioxide cleaner, by blasting air into carbon dioxide cleaner, make CO2Removing.Wherein, E can be saltThe common inorganic acid such as acid, sulfuric acid is, it is preferable to use hydrochloric acid, in order to avoid SO is introduced during acid adding42-It is unfavorable to bring to subsequent processesIt influences.
Treated that water outlet enters preposition reverse osmosis units 6 for removing carbon dioxide unit 5, and preposition reverse osmosis units 6 are provided withReverse osmosis membrane assembly carries out reverse osmosis deaslination processing to waste water.Due to most of salt and whole organic matters cannot penetrate it is reverse osmosisThe water outlet of removing carbon dioxide unit 5 is divided into two streams by membrane module, therefore, reverse osmosis membrane assembly, i.e., containing less salinityThe preposition reverse osmosis preposition reverse osmosis concentrated water F through water G and rich in salinity and organic matter, preposition reverse osmosis transmission water G can be directIt recycles, preposition reverse osmosis concentrated water F then enters subsequent processing units.In a preferred embodiment, preposition reverse osmosis listThe reverse osmosis membrane assembly of member 6 can be multisection type, such as two-part, be formed most using different types of a variety of reverse osmosis membrane assembliesWhole processing unit, to improve desalting effect.
The preposition reverse osmosis concentrated water F of preposition reverse osmosis units 6 enters second medium filter element 7 and is handled, due to needingIt wants useless Organic substance in water and the scale-forming ion content of zero discharge treatment usually higher, changes greatly, in addition the salt of waste water itself containsMeasure also higher, therefore, flocculant and coagulant adds in the flocculation described in clarification pliable cell 1 and clarification softening processAmount may be excessive, these flocculants, coagulant and its reaction product cannot be complete before waste water enters preposition reverse osmosis units 6Removal, is concentrated, impurity, colloid and SDI value are all increased, if not further this portion in preposition reverse osmosis concentrated water FDivide substance removal, will affect the operation of subsequent reverse osmosis units, it is therefore desirable to further filtering removal.Second medium filtering is singleMember 7 is provided with medium filter, by one or more filter mediums to filtration treatment.By second medium filter element 7Filtration treatment, the subsequent stable operation under high pH conditions of reverse osmosis units 8 can be made.
The common class in this field all can be used in the medium filter form and medium type that second medium filter element 7 usesType and type, for example, first medium filter element 2 those of is related to.It can also be according to water quality situation appropriate adjustment.
The water outlet of second medium filter element 7 enters reverse osmosis units 8 and carries out reverse osmosis treatment, and reverse osmosis units 8 are arrangedThere is reverse osmosis membrane assembly, reverse osmosis treatment is carried out to waste water.In a preferred embodiment, relative to preposition reverse osmosis units6, reverse osmosis units 8 select the reverse osmosis membrane assembly for being suitable for more high salinity, since its salt content is higher, operating pressureIt is higher, it can reach about 4.0~8.0MPa.The water outlet of second medium filter element 7 is divided into two streams by reverse osmosis units 8,That is reverse osmosis the reverse osmosis concentrated water I, reverse osmosis transmission water H through water H and rich in salinity and organic matter containing less salinityIt can directly recycle, the salt content in reverse osmosis concentrated water I then reaches about 7%, the as-salt concentrated water for salt recycling.
The third aspect of the invention provides a kind of salt recovery method of brine waste, for de- to the brine wasteResulting sodium chloride-containing after salt treatment, sodium sulphate, sodium nitrate-salt concentrated water carry out salt recycling, referring to Fig.1 shown in system, packetInclude following processing step:
- salt concentrated water I is carried out nanofiltration processing by the first nano-filtration step；
Ozone oxidation step, the first nanofiltration retentate fluid J that the first nano-filtration step is generated carry out ozone Oxidation Treatment；
The water outlet of ozone oxidation step is carried out adsorption treatment by chelating resin adsorption step；
The water outlet of chelating resin adsorption step is carried out Freeze crystallization and recycles sodium sulphate by sodium sulphate freezing and crystallizing stepCrystal, while water outlet is back to the first nano-filtration step；
The first nanofiltration permeate liquid K that first nano-filtration step generates is evaporated at crystallization by sodium chloride evaporative crystallization stepsReason, outlet evaporates mother liquor L to recycling sodium chloride product M simultaneously；
The evaporation mother liquor L of sodium chloride evaporative crystallization steps is carried out Freeze crystallization and returned by sodium nitrate freezing and crystallizing stepReceive sodium nitrate product P；And
Sodium nitrate freezing and crystallizing water outlet O is carried out nanofiltration processing, and the second nanofiltration retentate fluid T is returned by the second nano-filtration stepIt is back to ozone oxidation step to be handled, the second nanofiltration membrane permeate W is back to sodium chloride evaporative crystallization steps and is handled.
In a preferred embodiment, in ozone oxidation step, O3Dosage can be in the first nanofiltration retentate fluid J1~5 times of COD total amount, catalytic oxidation time can be 60~300 minutes.
In a preferred embodiment, the concentration of sodium nitrate can be in the outlet mother liquor of sodium chloride evaporative crystallization steps700~1800g/L；In a more preferable embodiment, the concentration of sodium nitrate can be 800~1500g/L.
In a preferred embodiment, sodium nitrate freezing and crystallizing step further includes to the outer of sodium chloride evaporative crystallization stepsDemineralized water is added in row mother liquor L to dilute the outlet mother liquor, the additional amount of demineralized water is the 5~100% of the outlet mother liquor.
In a preferred embodiment, the cryogenic temperature in sodium nitrate freezing and crystallizing step can be -5~50 DEG C；?In one more preferable embodiment, the cryogenic temperature in sodium nitrate freezing and crystallizing step can be 0~10 DEG C.
Salt recovery method provided by the invention can isolated operation, for-salt concentrated water resulting after desalting processing carry out salt returnIt receives, is not limited to the source of-salt concentrated water, as long as wherein containing salt such as sodium chloride, sodium sulphate, sodium nitrate.Salt of the invention returnsReceiving method also can be used as some processes and be used among the treatment process of brine waste.
The fourth aspect of the invention provides a kind of processing method of brine waste comprising following steps:
S1: desalting processing is carried out to brine waste to be processed, recycling produces water and obtains sodium chloride-containing, sodium sulphate, nitric acidThe-salt concentrated water of sodium；
S2: salt is carried out using salt recovery method described in third aspect of the present invention the resulting-salt concentrated water of step S1 and is returnedIt receives.
In a preferred embodiment, can successively include following processing step for desalinating process of the invention:
Clarify bating step, to brine waste A to be processed add medicament B clarified, sofening treatment；
First medium filtration step is filtered processing to the water outlet of clarification bating step；
The water outlet of first medium filtration step is carried out film filtration treatment by membrane filtration step；
Resin cation bating step is carried out by cation exchange resin the film filtration effluent D of membrane filtration step softChange processing；
The water outlet of resin cation bating step is carried out CO by removing carbon dioxide step2Removing processing；
The water outlet of removing carbon dioxide step is carried out reverse osmosis deaslination processing by preposition reverse osmosis step；
Second medium filtration step is filtered processing to the preposition reverse osmosis concentrated water F of preposition reverse osmosis step；And
The water outlet of second medium filtration step is carried out reverse osmosis deaslination processing, gained reverse osmosis concentrated water I by reverse osmosis stepAs sodium chloride-containing, the-salt concentrated water of sodium sulphate, sodium nitrate.
Waste water treatment system and processing method of the invention is applicable to common petrochemical industry, coal chemical industry, fine chemistry industry, power generationThe waste water that the industries such as factory generate, especially high saliferous contain organic wastewater, can all have a certain amount of chlorine in these usual waste waterCompound, nitrate and sulfate are very suitable to using processing system and processing method of the invention.
In the following, present invention be described in more detail by embodiment.
Embodiment
Brine waste processing is carried out as steps described below.
A, brine waste to be processed, organic concentration are as follows: CODcr150mg/L, TDS:8000mg/L, hardness (withCaCO3Meter) 400mg/L, basicity is (with CaCO3Meter) 200mg/L, suspended matter 5mg/L.Sodium hydroxide, coagulation are added in brine wasteThe medicaments such as agent PFS, soda ash, flocculant PAM, oxidant NaClO enter the clarification of clarifying basin row, sofening treatment.Wherein, 40% hydrogen-oxygenChange 1.5kg/ tons of water of sodium dosage, coagulant charging quantity 15ppm, 0.4kg/ tons of water of soda ash dosage, flocculant dosage1.5ppm, oxidant dosage 50ppm (in terms of effective chlorine composition).
Clarifying basin uses high efficiency clarification tank, and clarifying basin inclined plate area's upflow velocity is designed by 2.2-2.5mm/S.Clarifying basin water outletSuspended matter is less than 10mg/L, and hardness is less than 100mg/L (with CaCO3Meter), CODcr is less than 115mg/L.
B, clarifying basin water outlet is promoted by pump is sent into more medium filter, the built-in quartz sand of more medium filter and anthracite,Wherein, quartz sand filling height is 800mm, and anthracite filling height is 400mm, filtering velocity 7.0m/h.More medium filter water inletAdd acid for adjusting pH value to 7.5-7.8 range, more medium filter goes out aqueous suspension less than 2mg/L, and turbidity is less than 5NTU, CODcrLess than 105mg/L.
C, more medium filter water outlet enters ultrafiltration membrane treatment system, and ultrafiltration membrane uses Asahi Chemical Industry UNA-620A type external-compression typeUltrafiltration membrane, filtration flux 50Lmh/m2.At this point, the water rate of recovery is 95%, aqueous suspension ≈ 0mg/L, delivery turbidity are less than out0.1NTU, water outlet CODcr are less than 100mg/L, are discharged SDI value less than 3.
D, ultrafiltration production water enters ultrafiltration pond, is lifted into weak acid cation bed through pump, and weak acid sun is filled in weak acid cation bedIon exchange resin, weak acid cation bed design current velocity 22m/h, hardness is (with CaCO in water outlet3Meter) it is less than 1mg/L.Adsorption saturationResin regeneration of hydrochloric acid, regeneration period are 72 hours.
E, aforementioned water outlet adds hydrochloric acid, makes pH value to 4.3 or so, into decarbonizer, while blasting air into decarbonizer,Make CO2Removing.CO in decarbonizer water outlet2Concentration is about 5mg/L or less.
F, decarbonizer water outlet plus alkali adjust pH value to 8.5 or more (or the pH value of control concentrated water side is between 10.5-11) intoEnter preposition reverse osmosis membrane apparatus, the pollution-resistant membrane (one of different pressure levels is respectively adopted in two sections of preposition reverse osmosis membrane apparatus designsDuan Caiyong Tao Shi BW30FR-400/34i film original part, two sections use XFRLE-400/34i film original part), with 18Lmh/m2DesignFlux, carries out reverse osmosis treatment, and the reverse osmosis water rate of recovery is 70%.Reverse osmosis produced water TDS is less than 300mg/L, reverse osmosis concentratedWater TDS about 27000mg/L, reverse osmosis concentrated water CODcr 330mg/L.
G, reverse osmosis produced water recycles, and concentrated water enters more medium filter, and filtrate uses quartz sand and anthracite,In, quartz sand filling height is 800mm, and anthracite filling height is 400mm, filtering velocity 7m/h.SDI is less than 5 for filter water outlet, turbidDegree is less than 1NTU.
H, more medium filter water outlet enters reverse osmosis membrane treatment system, and reverse osmosis membrane assembly is rich resistance to anti-using Tao Shi XC70Permeable membrane original part, operating pressure 6.0MPa design flux 17Lmh/m2, the reverse osmosis water rate of recovery is 60%.Reverse osmosis produced waterTDS is less than 550mg/L, concentrated water TDS about 67000mg/L, CODcr 820mg/L.
I, reverse osmosis concentrated water enters the first nanofiltration membrane component system, and nanofiltration membrane component uses GE company DK8040 type nanofiltration membraneComponent.Nanofiltration permeate liquid CODcr 80mg/L, into sodium chloride evaporated crystallization device；CODcr in nanofiltration membrane trapped fluid5000mg/L, SO42-Concentration reach about 90g/L, into ozone-oxidizing device.
J, in ozone-oxidizing device, O is passed through into waste water3, ozone-oxidizing device thtee-stage shiplock, built-in filler and distributionDevice, ozone-oxidizing device is using oxygen as gas source, ratio of height to diameter 10, and the dosage of ozone is to throw in every cubic metre of nanofiltration membrane trapped fluidAdd ozone 15kg, oxidation time of contact is 240 minutes, and through detecting, COD concentration is 760mg/L in waste water after ozone oxidation.
K, the water outlet of ozone-oxidizing device enters resin adsorption device, and resin adsorption device is chelating bed, and chelating bed is built-inD851 type chelating resin, after tested, chelating bed go out the water hardness (with CaCO3Meter) it is 50~100ppb, resin adsorption device is againRaw waste liquid returns to clarification softening pond.
L, resin adsorption device water outlet enters sodium sulphate freezing and crystallizing separator, in sodium sulphate freezing and crystallizing separatorIt is interior, water temperature is cooled to 2 DEG C first, sodium sulphate reaches hypersaturated state and is precipitated in crystalline form, then will by centrifuge separationSodium sulfate crystal is separated from solution.
M, the solution being centrifugated in sodium sulphate freezing and crystallizing separator returns to the water inlet end of the first nanofiltration membrane component.
N, the nanofiltration permeate liquid that i step generates enters sodium chloride evaporated crystallization device, and sodium chloride evaporated crystallization device usesTwo effects are evaporated under reduced pressure, and 80 DEG C of evaporating temperature, the sodium chloride product purity of recycling meets industrial application requirement, steam up to 99.2%Send out the outer discharge capacity 3% of mother liquor.
O, the outlet evaporation mother liquor of sodium chloride evaporated crystallization device enters sodium nitrate freezing and crystallizing device, while adding 10%Demineralized water dilution, and solution temperature is reduced to 2 DEG C, sodium nitrate reaches hypersaturated state and is precipitated in crystalline form, then passes throughCentrifuge separation separates nitric acid sodium crystal from solution, and the purity of sodium nitrate product meets industrial application up to 99.3%It is required that.
P, the solution being centrifugated in sodium nitrate freezing and crystallizing separator is heated to 20 DEG C, subsequently into the second nanofiltration membraneComponent system, the second nanofiltration membrane component use GE company DK8040 type nanofiltration membrane component.Nanofiltration operating pressure 2.0MPa, second receivesThe permeate CODcr 320mg/L of filter membrane component returns to sodium chloride evaporated crystallization device, CODcr in the second nanofiltration membrane trapped fluid6400mg/L, into ozone-oxidizing device.
By embodiment it is found that eliminating the big portion in brine waste by clarification softening, media filtration and ultrafiltration membrance filterPoint hardness, suspended matter and colloid, by low-acid cationic resin softening and decarbonizer eliminate remaining part temporary hardness andPermanent hardness (i.e. Ca2+、Mg2+、CO32-And HCO3-), then most water is recycled after preposition reverse osmosis treatment, saliferousWaste water is concentrated, and preposition reverse osmosis concentrated water has been filtered to remove colloid through more medium filter again, then again through counter-infiltration systemIt is secondary to have recycled most water.The concentrated water of counter-infiltration system realized after the first nanofiltration membrane sulfate and organic matter retention andThe permeate of concentration, the first nanofiltration membrane obtains solid sodium chloride through evaporative crystallization, and the sodium chloride evaporation mother liquor of outlet is through sodium nitrateThe crystallization and separation of sodium nitrate are realized after the separation of freezing and crystallizing device, then the solution realizes again after the second nanofiltration membraneThe retention and separation of sulfate and organic matter avoid the enrichment of sulfate and organic matter in evaporated crystallization device.And firstThe trapped fluid of nanofiltration membrane eliminates most of organic matter therein after ozone oxidation, then hardness drops after chelating bed resin adsorptionAs low as 0.01mg/L hereinafter, realizing the crystallization and separation of sodium sulphate after the separation of sodium sulphate freezing and crystallizing device, return againThe concentration that sodium sulphate is carried out to the first nanofiltration membrane treatment unit avoids the enrichment such as organic matter, heavy metal and causes to endanger to nanofiltration membraneEvil.
By these processing steps, organic matter, the salt in brine waste can be separated from water, obtain the solid chlorine of high qualityChange sodium, sodium sulphate, sodium nitrate and recycle product, and is a small amount of mainly by CaCO3With Mg (OH)2The inoganic solids waste of composition, will notGenerate the unserviceable mixed salt containing organic matter.Method and system of the invention can also effectively prevent organic matter and scale-forming ionEnrichment, it is ensured that system can it is long-term, stablize, reliability service, without secondary pollution, there is significant economic benefit and Environmental EffectBenefit.
Although with reference to exemplary embodiment describes the present invention, it is to be understood that, term used be explanation and it is exemplary,Term and not restrictive.Since the present invention can be embodied in a variety of forms without departing from spirit or essence of the invention,It should therefore be appreciated that above-described embodiment is not limited to any of the foregoing details, and should in spirit as defined in the appended claims andIt is widely explained in range, therefore the whole change and modification fallen into claim or its equivalent scope all should be appended rightIt is required that being covered.