A kind of percolate deep purifying treatment unit and method
Technical field
The present invention relates to sewage treatment area, the present invention relates to a kind of percolate deep purifying treatment unit and method particularly, particularly relate to a kind of technique be applied in high concentrated organic wastewater advanced treatment process, be applicable to burn power plant's landfill leachate treatment industry, also can be applicable to landfill percolate and other high concentrated organic wastewater industries.
Background technology
Along with the development of economy, the protection of ecotope and resource utilize the focus becoming people's growing interest rationally and effectively.At present serious in China's environmental pollution, the discharge of trade effluent and urban domestic wastewater causes the pollution of environment, and especially consumer waste infiltration liquid is more serious to environmental hazard, and the overexploitation of water resources and use, make China face serious water crisis simultaneously.
The crisis of current facing mankind water has been undisputable fact; although country adds the input to urban infrastructure construction and environment protection; strengthening comprehensive environmental improvement; thus gross contamination emission is effectively controlled; some areas and city environmental quality make moderate progress, but environmentally monitoring result statistical study, China's water pollutions situation is still very severe; every gross contamination emission is very large, and pollution level is still in quite high level.
Meanwhile, along with urbanization degree is accelerated, water consumption increases, and water displacement increases simultaneously, and sewage disposal demand also strengthens thereupon, sewage disposal is regenerated, and the utilization of reuse water also becomes the effective way alleviating Water Resources Pressure.
In various sewage, percolate Organic pollutants concentration is high, ammonia nitrogen concentration is high and containing a large amount of soluble solid and heavy metal ion, if do not dealt carefully with, severe contamination can be caused to the water body of surrounding and soil, to the healthy generation serious threat of the periphery people.
More and more stricter to the requirement of effluent quality after landfill leachate treatment at present, especially for the percolate that burning power plant produces, the recirculated cooling water moisturizing standard that some ring major river valley regional requirements percolate water outlets reach " urban wastewater treatment firm pollutant emission standard " middle one-level emission standard A or reach in " urban sewage reutilization industry water standard " standard (GB/T19923-2005).Therefore the advanced treatment of percolate be one in the urgent need to technology.
The further treatment technique of existing MSW Incineration Plant percolate is as shown in Figure 1: its technical matters flow process is that filter and reverse osmosis process are directly received in MBR water outlet, wherein nanofiltration generally adopts pollution-resistant membrane, the fresh water productive rate of nanofiltration technique is about 75% ~ 85%, percolate after nanofiltration process is again through reverse osmosis process, reverse osmosis process many employings brackish water or sea water desalination membrane, the fresh water productive rate of reverse osmosis is about 70% ~ 75% of flooding quantity, then entire depth treatment system fresh water productive rate is about 50% ~ 60%.
Select nanofiltration+reverse osmosis process of the prior art, water outlet can meet the recirculated cooling water moisturizing standard in one-level A standard or reuse water, but after nanofiltration and reverse osmosis, a large amount of dense water can be produced, wherein the dense water of nanofiltration contains a large amount of divalent-metal ions and the organic pollutant of difficult degradation, and its dense water production rate is about 15% ~ 25%; Reverse osmosis concentrated water is containing higher salinity, and dense water generation is about 25% ~ 30%; Then the total dense water production rate of system is about 50% ~ 60%.And do not have economically viable way temporarily for the dense water treatment of percolate in industry, in the face of so many dense water, burn power plant's reuse and have difficulties.
Although art methods can realize one-level emission standard A or GB/T19923-2005 standard, nanofiltration concentrated solution productive rate is about 15% ~ 25% of flooding quantity, and reverse osmosis concentrated liquid productive rate is about 25% ~ 30% of feed water by reverse osmosis amount; Because nanofiltration concentrated solution and reverse osmosis concentrated liquid water quality difference are greatly, adopt the mode of reuse respectively to dispose, but no matter adopt which kind of disposal options, so many concentrated solution is all a difficult problem concerning power plant.
For the predicament faced in industry, develop a kind of economical rationality, technical feasibility further treatment technique scheme imperative, to reduce dense water generation, ensure that the dense water yield meets power plant's reuse requirement.
Summary of the invention
In summary of the invention part, introduce the concept of a series of reduced form, this will further describe in embodiment part.Summary of the invention part of the present invention does not also mean that the key feature and essential features that will attempt to limit technical scheme required for protection, does not more mean that the protection domain attempting to determine technical scheme required for protection.
One aspect of the present invention provides a kind of percolate deep purification treatment method, comprising:
(1) membrane bioreactor is selected to process percolate, to remove organism in described percolate and solid particulate;
(2) materialization coagulation is carried out in the water outlet of membrane bioreactor in step (1), to form precipitation and colloid;
(3) feed separation is carried out to the water outlet of step (2), remove described precipitation and colloid, go out water hardness and turbidity to reduce this;
(4) reverse-osmosis treated is carried out to the water outlet of step (3), to remove the ion in this water outlet.
As preferably, the materialization coagulation in step (2) comprises following sub-step:
(2-1) pH regulator is carried out, by pH regulator to alkalescence to the water outlet of membrane bioreactor in step (1);
(2-2) sterilization is carried out to the water outlet of step (2-1);
(2-3) flocculation treatment is carried out to the water outlet of step (2-2), to form precipitation or colloid in described water outlet.
As preferably, by pH regulator to 11.5 ~ 12.5 of described water outlet in described step (2-1).
As preferably, in described step (2-3), add the water outlet of flocculation agent to described step (2-2) carry out flocculation treatment.
As preferably, in described step (2-3), add the water outlet of coagulant aids to described step (2-2) carry out flocculation treatment.
As preferably, also comprise the pH regulator of the water outlet of step (3) between described step (3) and described step (4) to the step of weakly acidic pH.
As preferably, the CODcr of the water outlet after Membrane Bioreactor for Wastewater Treatment controls at 800 ~ 1200mg/L in (1) by described step.
As preferably, in described step (4), the concentrated solution producing water ratio of reverse osmosis controls between 25 ~ 30%.
Present invention also offers a kind of percolate deep purifying treatment unit, comprising:
Membrane bioreactor, for removing the organism in percolate;
Materialization coagulation system, for carrying out flocculation treatment to percolate;
Feed separation system, is used for realizing solid-liquid separation, reduces hardness and the turbidity of percolate;
And reverse osmosis system, with removing percolate intermediate ion.
As preferably, described membrane bioreactor is immersion curtain type membrane or external placed type tubular membrane.
As preferably, described materialization coagulation system comprise be communicated with successively pH regulator pond, sterilization pool, coagulation reaction tank, to realize pH regulator to percolate, sterilization and flocculation treatment.
As preferably, in described feed separation system, feed separation film is selected to carry out solid-liquid separation.
As preferably, in described reverse osmosis system, select brackish water film or sea water desalination membrane.
Beneficial effect of the present invention is:
(1) employing materialization coagulation and membrane separation process replace the nanofiltration technique in existing film further treatment technique, avoid the dense water of nanofiltration technique stage generation, improve whole system fresh water generation;
(2) system producing water ratio improves, and fresh water reuse amount increases, and saves power plant's running cost;
(3) the invention solves dense water generation large, the predicament that power plant cannot dissolve;
(4) present invention, avoiding the generation of nanofiltration stage concentrated solution, decrease the laying of NF concentrated water reuse pipeline, save one-time investment;
(5) nanofiltration concentrated solution reuse power plant is avoided, to the phenomenon such as equipment corrosion, fouling that power plant causes.
Accompanying drawing explanation
Following accompanying drawing of the present invention in this as a part of the present invention for understanding the present invention.Shown in the drawings of embodiments of the invention and description thereof, be used for explaining principle of the present invention.In the accompanying drawings,
Fig. 1 is the advanced treatment process schema of MSW Incineration Plant percolate in prior art;
Fig. 2 is the advanced treatment process schema of MSW Incineration Plant percolate of the present invention.
Embodiment
In the following description, a large amount of concrete details is given to provide more thorough understanding of the invention.But, it will be apparent to one skilled in the art that the present invention can be implemented without the need to these details one or more.In other example, in order to avoid obscuring with the present invention, technical characteristics more well known in the art are not described.
The present invention is too much in order to solve the dense Water Sproading existed in prior art, the problem of complex process, provide a kind of new percolate deep purification treatment method, described method adopts materialization coagulation+feed separation+reverse osmosis process as the advanced treatment process of percolate.
Wherein, employing materialization coagulation and membrane separation process replace the nanofiltration technique in existing film further treatment technique, avoid the dense water of nanofiltration technique stage generation, improve whole system fresh water generation.
At materialization coagulation process primarily of pH regulator pond, sterilization pool, coagulation reaction tank composition, main purpose is flocculated at the suspended substance in the percolate of life process and colloid, forms flco.
Wherein, feed separation is a kind of membrane separation process, application feed separation film, and the passage of this film is comparatively large, flux is comparatively large, can bear larger working pressure.
Wherein, reverse osmosis membrane mainly adopts brackish water or sea water desalination membrane, depending on whether having requirement to water outlet chlorion, as water outlet has chlorion requirement, then adopts sea water desalination membrane, as direct discharge, then adopts brackish water film.
Embodiment 1
Be further described a kind of preferred implementation of the present invention below in conjunction with accompanying drawing, as shown in Figure 2, the technical program technical process is: MBR water outlet+materialization coagulation+feed separation membrane sepn+reverse osmosis process.
(1) MBR technique
The film of MBR technique both can be immersion curtain type membrane also can be external placed type tubular membrane, and the CODcr of its effluent quality controls at 800 ~ 1200mg/L;
Described MBR technique not only increases the effluent quality of system and the stability of operation, also extends the hydraulic detention time of macromolecular substance in bio-reactor, makes it to be degraded to greatest extent, and strengthens the removal effect of system to hard-degraded substance.
Described MBR reactor comprises the step of nitrification and denitrification in this embodiment:
Denitrification: first the water outlet of anaerobic technique enters denitrification pond, under anaerobic environment, the nitric nitrogen in water inlet and return digestion liquid and nitrite nitrogen are reduced into nitrogen and discharge by microorganism, reach the object of biological denitrificaion; Affect denitrifying factor and mainly contain 2 points, one is control the concentration of dissolved oxygen between 0 ~ 0.5mg/L, and two is ensure denitrifying carbon source, and carbon source concentration is generally between 4 ~ 6 times into water total nitrogen concentration.
Nitrated: the percolate behind denitrification pond enters nitrification tank and carries out nitration reaction, the effect of nitrification tank mainly contains 2 points, and one is the remaining organic pollutant of degraded, and two is under ammonification, convert ammonia nitrogen to nitric nitrogen and nitrite nitrogen.
As preferably, can also according to removal ratio organic in percolate after denitrification step, selectivity increases strengthened denitrification step, particularly, the waste water after nitrated enters strengthened denitrification system, i.e. rear-mounted denitrification, additional carbon is added to obtain higher TN clearance in rear-mounted denitrification, nitric nitrogen can more be broken down into nitrogen and remove, and TN clearance improves further, saves running cost simultaneously.
As further preferred, the water outlet after biochemical treatment is again through ultrafiltration membrance filter.The effect of described ultra-filtration membrane mainly contains 2 points, and the first maintains the sludge concentration in biochemistry pool, and its sludge loading is improved; It two is filter water outlet, tackles more macromolecular organic pollutant.Ultra-filtration membrane both can be immersion curtain type membrane also can be external placed type tubular membrane, and the CODcr of its effluent quality controls at 800 ~ 1200mg/L.
(2) materialization coagulation process
Materialization coagulation process is made up of the step such as adjustment, sterilization and disinfection, coagulating of pH, carries out pH regulator, pH value is adjusted to 11.5 ~ 12.5, usually select the method adding alkali lye to regulate to the water outlet through MBR process.PH regulator arranges pH meter in pond, pH meter and alkali lye throwing device chain, realize pH regulator and automatically control.
Water outlet after pH regulator enters sterilization pool and carries out sterilization, it mainly carries out germicidal treatment by adding oxidizing species to percolate, in this step on the one hand can sterilization algae removal, reduce the living organism amount retained by ultra-filtration membrane, thus the material separator applied in guarantee subsequent disposal and reverse osmosis membrane be not by the pollution that bacterium algae grows, guarantee steady in a long-term operation.
In this embodiment, can DBNPA(2 be added, 2-dibromo-3-nitrilo-proprionamide, the two bromo-3-nitrilo-propionic acid amide of 2,2-), the sterilant such as clorox or hydrogen peroxide carries out sterilization.Wherein DBNPA is non-oxidative antimicrobial, and compatible with mould material, it adds film without impact.Hydrogen peroxide and clorox are strong oxidizing property sterilant, add concentration and dosage has requirement when adding to it, and the concentration of hydrogen peroxide is not higher than 0.2%, and clorox concentration is no more than 10%, causes damage to prevent described sterilant to mould material.The concrete dosage of sterilant will be determined according to actual water quality situation.
Add flocculation agent in water outlet after sterilisation step, make percolate generation flocculation reaction, owing to containing a large amount of HCO in percolate
3-, when adding alkali lye and solution ph being adjusted to 12, a large amount of CO can be generated
3 2+, and with the Ca in water
2+, Mg
2+reaction forms CaCO
3, MgCO
3precipitation, iron ion and OH in solution
-ionic reaction forms Fe (HO)
3colloid, and described precipitation and colloid being removed, to reduce hardness in water and turbidity.
In order to better by described CaCO
3, MgCO
3precipitation and Fe (HO)
3colloid is removed, in percolate, add flocculation agent, by add flocculation agent make the precipitation that formed in percolate or colloid more stable, and by its aggregation property, these particles are concentrated, obtain more closely knit precipitation, thus be more prone to be separated.Wherein flocculation agent can aluminium salt or molysite, and as preferably, described flocculation agent selects the molysite of 5% (massfraction is the iron salt solutions of 5%) its dosage for being less than or equal to 150ppm.
As preferably, coagulant aids can also be added further to improve flocculating effect, described coagulant aids also can improve the structure of flocs unit, utilize the strong adsorption bridging action of polymer coagulant aids, tiny loose flocs unit is made to become thick and tight, conventional be its dosage of anionic polyacrylamide depending on water quality situation, as preferably, its dosage is that the solution dosage of 0.1 ‰ ~ 0.15 ‰ concentration is for being less than or equal to 3ppm.
(3) feed separation
Described feed separation step is also a kind of membrane separation process, by this step, the precipitation, colloid and the percolate that are formed in materialization coagulation step are separated, realize solid-liquid separation, remove the most of solid particulate in water, reduce hardness and the turbidity of percolate.
Select feed separation film to carry out solid-liquid separation in this step, this feed separation film has porous, high strength, erosion resistance, chemical stability, flux is large, easy cleaning, can the advantages such as working pressure scope is wide.The working pressure of this film is between 0.05 ~ 0.1MPa, and flux can reach 100 ~ 200L/m
2h.
The solid particulate in water is not removing only in the coagulation process of materialization described in the present invention and feed separation technique, reduce hardness and the turbidity of percolate, also can not produce dense water simultaneously, thus reduce dense water production rate in whole processing step, improve the fresh water generation of whole system, avoid and select diverse ways to process respectively the dense water produced in different step, make whole technological process more simple, efficient, process costs reduces.
The precipitation removed in this step, colloid and mud can be discharged in sludge storage pool, carry out reclaiming and utilizing.
After feed separation, eliminate the Ca in most percolate
2+, Mg
2+and Fe
2+/ Fe
3+, its removal effect is as shown in table 1, and this step also has certain effect to the removal of COD.
Feed separation film service data of the present invention is as shown in table 1:
|
MBR water outlet |
Feed separation membrane filtration clear liquid |
Clearance % |
Ca(mg/L) |
185 |
22 |
88.11% |
Mg(mg/L) |
287 |
14.5 |
94.95% |
COD(mg/L) |
653 |
457 |
30.02% |
(4) reverse osmosis process
Under the effect of pressure difference, the impurity such as salt, heavy metal in percolate is removed in this step, to the further separation and purification of percolate, to reach emission standard by reverse osmosis membrane.
Reverse osmosis membrane mainly adopts brackish water or sea water desalination membrane in this step, depending on whether having requirement to water outlet chlorion, as water outlet has chlorion requirement, then adopt sea water desalination membrane, as direct discharge, then adopt brackish water film, reverse osmosis concentrated water producing water ratio controls between 25 ~ 30%.
As preferably, the step of described percolate being carried out to pH regulator can also be comprised before carrying out reverse-osmosis treated, particularly, by adding acid in percolate, in and the excessive alkali that adds in pH regulator pond, make last water outlet as far as possible for neutral, water outlet is directly applied, the pH adjusting agent that the kind of the acid wherein added can select this area conventional, is not limited to a certain, does not repeat them here.
The water quality (reverse osmosis adopts brackish water film) of the percolate after process of the present invention is as shown in table 2, finds out that described CODcr and TDS all significantly reduces pole in this step, has good effect, reaches emission standard from this table.
Table 2 reverse osmosis adopts the water quality of the percolate of brackish water film
Water quality classification |
CODcrmg/L) |
TDSmg/L) |
The water outlet of feed separation film |
439 |
11758 |
Reverse osmosis 70% producing water ratio water quality |
21 |
875 |
Reverse osmosis 75% producing water ratio water quality |
37 |
1401 |
In order to solve the problem that in prior art, dense aquatic products rate is too high in the present invention, sewage treatment process is improved, and the order that arranges of each processing step is improved, to improve the treatment effect to percolate.First MBR technique is adopted to be removed the organic pollutant in percolate and larger solid particulate in the present invention, adopt coagulation-settlement process afterwards, feed water by reverse osmosis is softened, avoid reverse osmosis inorganic salt structure, improve the producing water ratio of reverse osmosis and reduce the cleaning frequency of reverse osmosis, while reaching emission standard, reduce dense aquatic products rate, solve the drawback existed in prior art.
Embodiment 2
Present invention also offers a kind of percolate deep purifying treatment unit, described device comprises the membrane bioreactor, materialization coagulation system, feed separation system and the reverse osmosis system that connect successively, wherein, described materialization coagulation system comprise be communicated with successively pH regulator pond, sterilization pool, coagulation reaction tank, for regulating percolate pH and forming flocculation sediment, to reduce hardness and the turbidity of percolate, do not produce dense water in this process simultaneously.
Wherein, feed separation system at least comprises feed separation film, to realize solid-liquid separation.
Particularly, membrane bioreactor can select the reactor that this area is commonly used in this embodiment, described reactor is made up of membrane module and bio-reactor two portions usually, the membrane module of described MBR technique both can be immersion curtain type membrane also can be external placed type tubular membrane, its principle of work is that a large amount of microorganisms (active sludge) fully contacts with matrix (labile organic compound etc. in waste water) in membrane bioreactor, carry out metabolism to maintain own growth, breeding by oxygenolysis, make organic pollutant degradation simultaneously; Then membrane module is acted on by mechanical grading, retain etc. and carries out solid-liquid separation to waste water and mud mixed liquid, and the CODcr of its effluent quality controls at 800 ~ 1200mg/L.Described MBR technique not only increases the effluent quality of system and the stability of operation, also extends the hydraulic detention time of macromolecular substance in bio-reactor, makes it to be degraded to greatest extent, and strengthens the removal effect of system to hard-degraded substance.
The reactor that described membrane bioreactor can be selected aerobic MBR, anaerobism MBR or both be combined.Wherein, aerobic MBR effluent quality is high, controls described aerobic MBR rate of load condensate at 1.2 ~ 4.2kgCOD/ (m
3d), between, anaerobism MBR rate of load condensate is at 2.9 ~ 50kgCOD/ (m
3d) between; Anaerobism MBR can select as the case may be, when organic content is high especially in percolate or sewage, anaerobism MBR is selected to can be used as the pretreatment process of waste water or used water difficult to degradate, then according to the type of water quality, in conjunction with aerobic MBR process, make water outlet qualified discharge.
Wherein, materialization coagulation system is primarily of pH regulator pond, sterilization pool, coagulation reaction tank composition, through the water outlet of MBR process through pH regulator pond, by adding alkali lye, pH value is adjusted to 11.5 ~ 12.5, enter sterilization pool afterwards, sterilization pool mainly adds clorox, and coagulation reaction tank mainly adds flocculation agent and coagulant aids.Containing a large amount of HCO in percolate
3-, when adding alkali lye and solution ph being adjusted to 12, a large amount of CO can be generated
3 2+, and with the Ca in water
2+, Mg
2+reaction forms CaCO
3, MgCO
3precipitation, iron ion and OH in solution
-ionic reaction forms Fe (HO)
3colloid.By above reaction, the throw out that in solution, most calcium, magnesium, iron are formed and colloid, and precipitation is all flocculated by the silicate carried.
The precipitation, colloid and the percolate that are formed in materialization coagulation step with reference to the setting of membrane module in MBR, can be separated by feed separation film, realize solid-liquid separation by arranging of the feed separation film in described feed separation system.
Aperture is utilized to be the reverse osmosis membrane (RO film) of 1/10000 μm in reverse osmosis unit, the water of higher concentration is made to become low concentration of water, the impurity be mixed in a large number in water such as industrial pollutants, heavy metal, bacterium, virus are all isolated simultaneously, thus reaching the physical and chemical index and hygienic standard of drinking regulation, output is to clear to pure water.
In this embodiment, described reverse osmosis system can comprise: pretreatment unit, reverse osmosis units, post-processing unit, cleaning unit and electric control unit etc.
Wherein reverse osmosis units, mainly comprises the compositions such as multistage high-pressure pump, reverse-osmosis membrane element, putamina (pressurized vessel), support.Its Main Function removes the impurity in water, water outlet is made to meet service requirements, brackish water or sea water desalination membrane is selected in described reverse-osmosis membrane element, depending on whether having requirement to water outlet chlorion, as water outlet has chlorion requirement, then adopt sea water desalination membrane, as direct discharge, then adopt brackish water film, reverse osmosis concentrated water producing water ratio controls between 25 ~ 30%.
Certain described reverse osmosis system is not limited to above-mentioned configuration, can arrange according to concrete needs.
By apparatus and method of the present invention, make percolate after this advanced treatment process process, dense water generation controls within 30%, middle one-level emission standard A that water outlet reaches " urban wastewater treatment firm pollutant emission standard " or the recirculated cooling water moisturizing standard reached in " urban sewage reutilization industry water standard " standard (GB/T19923-2005).
The invention has the advantages that:
(1) employing materialization coagulation and membrane separation process replace the nanofiltration technique in existing film further treatment technique, avoid the dense water of nanofiltration technique stage generation, improve whole system fresh water generation;
(2) system producing water ratio improves, and fresh water reuse amount increases, and saves power plant's running cost;
(3) the invention solves dense water generation large, the predicament that power plant cannot dissolve;
(4) present invention, avoiding the generation of nanofiltration stage concentrated solution, decrease the laying of NF concentrated water reuse pipeline, save one-time investment;
(5) nanofiltration concentrated solution reuse power plant is avoided, to the phenomenon such as equipment corrosion, fouling that power plant causes.
The present invention is illustrated by above-described embodiment, but should be understood that, above-described embodiment just for the object of illustrating and illustrate, and is not intended to the present invention to be limited in described scope of embodiments.In addition it will be appreciated by persons skilled in the art that the present invention is not limited to above-described embodiment, more kinds of variants and modifications can also be made according to instruction of the present invention, within these variants and modifications all drop on the present invention's scope required for protection.Protection scope of the present invention defined by the appended claims and equivalent scope thereof.