One heavy metal species chemical leaching liquid waste disposal, recycling integrated device
Technical field
The utility model relates to heavy metal-polluted soil chemical leaching field of waste liquid treatment, is specially a heavy metal species chemical leaching liquid waste disposal, recycling integrated device.
Background technology
Along with the high speed development of industry and the quickening of urbanization process, the heavy metal pollution of soil situation of China is on the rise, and reparation and the improvement of heavy-metal contaminated soil have become very urgent.Propose a series of heavy metal soil restoring technology both at home and abroad at present, be mainly divided into peripheral doses technology, phytoremediation technology, microorganism remediation technology and chemical remediation technology etc.
In this several recovery technique above-mentioned, the chemical leaching method belonging to chemical remediation technology, mainly by reversing the reaction mechanism of soil sticking heavy metal, being transferred to heavy metal liquid phase from solid phase of soil, finally being reached the object of cleaning soil.Because pollutent can be removed fast by chemical leaching method from soil, can administer the contaminated soil of high density at short notice, oneself becomes one of the study hotspot and developing direction that heavy-metal contaminated soil is repaired fast at present.
Chemical leaching method working cost is relatively high, and the soil cost processing one ton of heavy metal contamination in the U.S. is 120 ~ 200 dollars.Mainly because the method needs the chemical leaching liquid of at substantial, and need to process ring waste.Therefore, when selecting suitable leacheate, except considering with the removal ability of its heavy metal and on except the impact of soil physico-chemical property and Soil Microorganism, whether its source and cost and waste liquid easily process also is the factor of main consideration.
At present, for the chemical leaching of heavy metal, acids drenches Xian's agent and sequestrant is the most frequently used reagent, and the PH of general leacheate is 4 ~ 5.In heavy metal leacheate composition, Na
2eDTA has very strong sequestering power, energy and most metal ion generation sequestering action, is to be considered to the most effective artificial sequestrant up to now.But Na
2eDTA is expensive, and ring waste needs the features such as subsequent disposal to hamper Na
2eDTA large-scale application in the wild.If Na
2eDTA can be reused by efficient recovery, and these problems just can solve.
Current process Na
2the method of EDTA elutant roughly can be divided three classes: (1) is with the heavy metal in zero-valent metal displacement EDTA complex compound, thus makes heavy metal precipitation, and EDTA also discharges again.(2) be electrolytic separation heavy metal and EDTA in a cell, separate with ion-exchange membrane between two-stage, stop electronegative EDTA at anode dissolution.(3) be add suitable chemical reagent EDTA inner complex is dissociated, thus precipitation of heavy metals.The advantages such as cost is low because chemical precipitation method has, applied range become the method that application is the most general at present.
But chemical precipitation method is generally in the basic conditions, heavy metal is made to generate BS, or sulfide precipitation.Because leacheate is acid, need the alkali of at substantial, if need the Na in the chemical leaching waste liquid after to process
2eDTA carries out reuse, then also need acid adding to adjust back.Therefore, operation relative complex, and a large amount of bronsted lowry acids and bases bronsted lowries can be wasted.All fail to solve this technical barrier both at home and abroad at present.
Membrane filtration is also a kind of method of physical sepn, but there is not been reported in its application in the process of heavy metal ring waste, although major cause is membrane filtration can improve organic efficiency, if but do not change treatment process, but simple employing membrane sepn replaces chemical precipitation method, its investment and running cost will increase greatly.In addition, because heavy metal ring waste complicated component, acid/alkalescence are higher, certain requirement is had to the material of film and structure, most widely used rolling organic membrane is relatively poor to degrees in the treatment of waste water, and easily pollute, therefore, membrane filtration be not suitable for process heavy metal ring waste.
Utility model content
The utility model aims to provide a heavy metal species chemical leaching liquid waste disposal, recycling integrated device, this ring waste process, recycling integrated device and treatment process are while recovery sequestrant, all right recovery part acid solution, not only organic efficiency is high, and the Ethylene recov impurity to be obtained by membrane filtration is few compared with chemical precipitation method, Ethylene recov quality is better, therefore, when the Ethylene recov adopting this device processes to obtain is reused, its drip washing effect is better than the Ethylene recov that chemical precipitation method obtains.
To achieve these goals, the technical scheme that the utility model adopts is:
One heavy metal species chemical leaching liquid waste disposal, recycling integrated device, is characterized in that, comprise
One settling tank; Ring waste is communicated with settling tank bottom by water inlet pipe, and the upper portion side wall of this settling tank has liquid outlet;
One ring waste reaction tank; The bottom of this ring waste reaction tank is communicated with the liquid outlet of described settling tank;
One is arranged on the MBR membrane module in ring waste reaction tank, and the liquid outlet of this MBR membrane module is communicated with a sequestrant collecting tank by water producing pipe;
One inorganic membrane filter, the fluid inlet of this inorganic membrane filter is communicated with the bottom of ring waste reaction tank;
The concentrated solution outlet of described inorganic membrane filter is communicated with ring waste reaction tank by return line, and the percolate outlet of this inorganic membrane filter is communicated with an acid solution pond for recovering.
Be below the technical scheme of further improvement of the utility model:
In order to realize precipitation better, described settling tank is tube settler, is provided with inclined tube filler, has slope bottom settling tank, be provided with mud hole at the bottom of slope in this tube settler.
As a kind of example preferably realizing ring waste and be communicated with settling tank bottom by water inlet pipe, settling tank flow deflector is provided with in described settling tank, have a segment distance at the bottom of this settling tank flow deflector and settling tank pond, described settling tank flow deflector and settling tank sidewall form the feed pathway with water inlet pipe outlet; As the example that a kind of bottom preferably realizing ring waste reaction tank is communicated with the liquid outlet of described settling tank, reaction tank flow deflector is provided with in described ring waste reaction tank, have a segment distance at the bottom of this reaction tank flow deflector and ring waste reaction tank pond, described reaction tank flow deflector and ring waste reaction tank sidewall form the liquid passage be excessively communicated with settling tank liquid outlet.
In order to ensure good filter effect, described inorganic membrane filter is inorganic ceramic nano-filtration membrane filter, filtering accuracy is 1KD ~ 20KD, and its effect is the inner complex retaining most of heavy metal ion in ring waste and heavy metal and EDTA, most acid solution in recovery ring waste.
In concentrated ring waste process, in order to better control be concentrated process, regulate the pressure in ring waste reaction tank pond, the return line of described inorganic membrane filter comprises external reflux pipe and internal reflux pipe, described external reflux pipe is communicated with the top of ring waste reaction tank, and described internal reflux pipe is communicated with the fluid inlet of described inorganic membrane filter.
In order to improve filtration efficiency, the fluid inlet of described inorganic membrane filter is provided with prefilter.
(Na is preferably at guarantee concentrated solution and alkali (being preferably NaOH) and/or sulfide
2s) reaction is more abundant, is provided with aerating apparatus at the bottom of described ring waste reaction tank pond.
Because ring waste is acid, do not meet the material working conditions of organic MBR film, therefore preferably described MBR membrane module is inorganic ceramic flat plate ultrafiltration membrane, and membrane pore size is 50nm ~ 200nm; Described MBR membrane module is all connected with corresponding back washing device with inorganic membrane filter, can ensure the design flux of strainer.
In order to ensure that concentrated solution and sulfide (are preferably Na
2s) hydrogen sulfide produced during reaction leaks, and described ring waste reaction tank is airtight pond, and Chi Ding is provided with discarded collection tube, passes in basic solution and process after collection.
Utilize above-mentioned heavy metal chemical leaching liquid waste disposal, recycling integrated device process ring waste, a method for reuse, comprise the steps:
1) ring waste enters 2h ~ 3h in settling tank by water inlet pipe, and supernatant liquor enters in ring waste reaction tank;
2) start inorganic membrane filter and carry out filtering and concentrating to the ring waste in ring waste reaction tank, the percolate after filtration passes in acid solution collecting tank, and when the cycles of concentration of ring waste is 4 ~ 6 times, inorganic membrane filter stops filtering;
3) in the concentrated solution in ring waste reaction tank, add alkali and/or sulfide, open the aerating apparatus be arranged at the bottom of ring waste reaction tank pond, reaction times 20 ~ 30min simultaneously;
4) start MBR membrane module to filter reacted concentrated solution, the percolate after filtration passes in sequestrant collecting tank.
In view of the inorganic ceramic film on inorganic materials science base has some incomparable advantages of polymer separation film: ceramic membrane rete is highly polished, and in multilayered structure and thin; The aperture of supporting layer increases gradually along the flow direction of penetrating fluid, and pore size distribution is step by step narrow, and porosity is high, thus has separation performance good, extremely low filtration resistance, and filtration flux is high; Fabulous resistance to crocking is had to feed liquid, can cleaning and regeneration repeatedly, flux stability is good, the advantages such as long service life.In addition, ceramic membrane chemical stability is good, applicable pH 0 ~ 14, can antimicrobial degraded.For organic solvent, etchant gas and microbial attack performance satisfactory stability.
Compared with prior art, the beneficial effects of the utility model are:
(1) while recovery sequestrant, all right recovery part acid solution, not only organic efficiency is high, and due to the filtering accuracy of film higher, the Ethylene recov impurity obtained by membrane filtration is few compared with chemical precipitation method, and Ethylene recov quality is better, therefore, when the Ethylene recov adopting this device processes to obtain is reused, its drip washing effect is better than the Ethylene recov that chemical precipitation method obtains.
(2) although inorganic ceramic film cost of investment is higher, long service life, is generally 5 ~ 8 years, is therefore converted to annual cost of investment and chemical precipitation method is more or less the same.
(3) this integration apparatus is simple to operate, can realize fully automatic operation; Floor space is little, and convenient transportation is flexible.
(4) due to the relative chemical precipitator method, not only sequestrant is reclaimed, and most acid solution can be reclaimed; The waste liquid being only less than 20% needs dosing, and Ethylene recov does not need acid adding to adjust back, and only needs sequestrant and the acid solution of supplementary partial loss.Although therefore its running cost is higher than chemical precipitation method, the economic benefit that its recovery produces is also higher than chemical precipitation method.
(5) owing to being employing physical filtering, therefore, as long as same equipment carries out simple adjustment according to practical situation be namely applicable to most heavy metal chemical leaching waste liquid, as chromium, cadmium, lead, nickel, arsenic etc.
Below in conjunction with drawings and Examples, the utility model is further elaborated.
Accompanying drawing explanation
Fig. 1 is the structure principle chart of the utility model embodiment.
In the drawings
1-ring waste water inlet pipe; 2-tube settler flow deflector; 3-inclined tube filler; 4-tube settler; 5-tube settler mud hole; 6-ring waste reaction tank flow deflector; 7-ring waste reaction tank; 8-ring waste reaction tank mud hole; 9-recycle pump; 10-prefilter; 11-inorganic ceramic film filter; 12-external reflux pipe; 13-internal reflux pipe; 14-penetrating fluid pipeline; 15-acid solution collecting tank; 16-recoils tank; 17-recoil tank tracheae; 18-chemical feed pipe; 19-air compressor machine; 20-aerating apparatus; 21-MBR membrane module; 22-MBR produces water pump; 23-MBR water producing pipe; 24-MBR backwashing pump; 25-MBR backwash pipe; 26-sequestrant collecting tank; 27-acid solution reuse pipe; 28-sequestrant reuse pipe; 29-ring waste reuse pump; 30-gas sampling pipe.
Embodiment
One heavy metal species chemical leaching liquid waste disposal, recycling integrated device, as shown in Figure 1, mainly comprise following components: 1) tube settler 4; 2) ring waste reaction tank 7; 3) inorganic ceramic film filter 11; 4) Ethylene recov collecting tank 15,26.
Described tube settler front end arranges flow deflector, first chemical leaching waste liquid enters bottom tube settler by guiding region, inclined tube filler is risen through by bottom, under the effect of inclined tube filler, at the bottom of large granular impurity in ring waste, solids precipitation to pond, clear liquid rising gravity flow enters ring waste reaction tank; Mudhole is had, the mud bottom periodic exhaustion bottom tube settler.The tube settler residence time 2 ~ 3h, there are flow deflector and inclined tube filler in inside, and side, bottom arranges slope, is conducive to the discharge of sediment, can not leave dead angle at the bottom of pond.
Ring waste reaction tank front end also arranges flow deflector, waste liquid after tube settler process first flows automatically and enters the guiding region of ring waste reaction tank, ring waste reaction tank arranges liquid level sensor, and when liquid level arrives high liquid level, tube settler front end stops theory of evolution ring waste.Now, inorganic ceramic film filter is opened.
The amount that the volume of ring waste reaction tank often criticizes ring waste according to process is determined.Its effect has two, and one is the circulatory pool as inorganic ceramic sodium filter membrane, can realize waste liquid circulate between ring waste reaction tank and inorganic ceramic film when acid solution reclaims; Another effect is dope process as reclaiming through acid solution and reuse reaction tank, after a small amount of agent-feeding treatment, realizes the reuse of sequestrant.
Ring waste reaction tank arranges liquid level sensor, and when waste liquid arrives high liquid level, tube settler front end stops water inlet, starts inorganic ceramic nanofiltration equipment and carries out acid solution recovery.Inorganic ceramic nanofiltration membrane adopts film imported, separation accuracy 1 ~ 20KD, and material is titanium dioxide; Except membrane element, subject apparatus all adopts stainless steel or other corrosion-resistant materials.Design flux 20 ~ 50L/h.m
2, adopt online combined water and air backwash system, alleviate membrane fouling rate.Cycles of concentration 4 ~ 6 times, 3 ~ 7 days matting cycles.Nanofiltration membrane can not reach 100% for the rejection of heavy metal, as being respectively 98 % and about 85 % to the rejection of nickel and cadmium.Therefore, reclaim in the acid solution obtained and also have the residual of a small amount of heavy metal ion, but for reuse, affect less.
First ring waste being pumped into inorganic ceramic film filter by recycle pump, in order to prevent large granular impurity from entering in inorganic ceramic film filter, between recycle pump and inorganic ceramic film filter, arranging prefilter after filtering and opening by inorganic ceramic film device; Filtration procedure is cross flow filter, and namely ring waste is entered by inorganic ceramic film filter bottom, flows out from top, and under the effect of recycle pump pressure, percolate flows out from membrane module both sides and enters acid solution collecting tank via percolate pipeline.And the dope part flowed out from top is back to ring waste reaction tank by external reflux pipe, another part is back in the pipeline of recycle pump front end by internal reflux pipe.Between inorganic ceramic film and ring waste reaction tank, constantly circulation is concentrated, until reach cycles of concentration for chemical leaching waste liquid.Too fast in order to prevent flux from declining, adopt the online combined water and air backwash system be made up of air compressor machine, connecting pipeline and recoil tank etc., alleviate membrane fouling rate.
After most of acid solution is reclaimed, start to process and reuse the dope in ring waste reaction tank.First, in ring waste reaction tank, a small amount of alkali and sodium sulphite is added by medicine system, by the aerating system at the bottom of air compressor machine and pond, medicament and ring waste are mixed, leacheate pH increases, the inner complex of heavy metal and EDTA can be hydrolyzed, the activation capacity of EDTA heavy metal ion is reduced, and the heavy metal ion in dope can generate sulfide precipitation and part precipitation of hydroxide, thus produces Na
2eDTA.When only adopting sodium sulphite just can reach good sedimentation effect for some heavy metal, alkali can not be added.
With the MBR ultra-filtration membrane bottom ring waste reaction tank to weakly alkaline Na
2eDTA solution reclaims, produce the suction function of water pump at MBR under, by the Na reclaimed
2eDTA solution flows into sequestrant collecting tank by MBR water producing pipe, for ensureing the flux stabilized of MBR ultrafiltration, regularly adopts backwashing pump to carry out backwash to it.Throw out is discharged by the discharge outlet of bottom.
Acid solution collecting tank is connected recycling pipeline and recovery pump with bottom sequestrant collecting tank, proportionally again can mix according to practical situation, adds the fresh acid solution of part and sequestrant, after making it reach service requirements, can carry out reuse.
Ring waste reaction tank top arranges cover plate, and H opened by cover plate
2s collection tube, collection tube connects to waste gas collecting system.Mainly consider that sulfide can produce toxic gas H in acid condition
2s, needs H
2s leads to and is equipped with in NaOH solution waste gas collecting system.
Whole plant main body of the present utility model is stainless steel or other corrosion-resistant materials, comprises pond body, pipeline, valve, membrane module shell etc.The nanofiltration that inorganic ceramic film adopts and ultra-filtration membrane are all inorganic ceramic film.
Dope amount after nanofiltration membrane concentrates is about the dope of 20% of ring waste amount.Now, in ring waste reaction tank, add a small amount of alkali and sodium sulphite by medicine system, and the aerating system opened at the bottom of pond makes medicament and ring waste mix, finally reclaimed by MBR film sequestrant.When only adopting sodium sulphite just can reach good sedimentation effect for some heavy metal (as cadmium, arsenic), alkali can not be added.Concrete chemical feeding quantity is determined according to heavy metal content in dope.
With the MBR ultra-filtration membrane bottom ring waste reaction tank, sequestrant is reclaimed, produce the suction function of water pump at MBR under, chelating agent solution flows into sequestrant collecting tank by MBR water producing pipe, for ensureing the flux stabilized of MBR ultrafiltration, regularly adopts backwashing pump to carry out backwash to it.Throw out is discharged by the discharge outlet of bottom.MBR film adopts inorganic ceramic flat plate ultrafiltration membrane, can acid-and base-resisting, organic solvent erosion, membrane pore size 50 ~ 200nm.The rate of recovery more than 80%, 1 ~ 3 month matting cycle.
The cubic capacity of acid solution collecting tank and sequestrant collecting tank is about often criticizes 60 ~ 90% of leacheate process volume, collecting tank arranges liquid level sensor respectively, when arriving high liquid level, Ethylene recov can by the recycling pipeline bottom collecting tank and recovery pump, proportionally again mix according to practical situation, after adding the fresh acid solution of part and sequestrant, reuse can be carried out.
Ring waste reaction tank top arranges cover plate, and H opened by cover plate
2s collection tube, collection tube connects to waste gas collecting system.Mainly consider that sulfide can produce toxic gas H in acid condition
2s, needs H
2s leads to and is equipped with in NaOH solution waste gas collecting system.
Whole technique adopts PLC automatic control system, can fully automatic operation.All ponds body, film device according to its running statuses of index automatic decision such as liquid level, flow, pressure, temperature, can ensure that whole system can steady running.
Treatment effect compares: adopt H
2sO
4+ Na
2eDTA obtains a collection of chemical leaching waste liquid after carrying out drip washing to the contaminated soil containing Pb, Cd.Adopt chemical precipitation method and aforesaid method to reclaim it respectively, the recovery medicament adopted in two kinds of recovery methods is all NaOH+Na
2s.The PH of chemical leaching waste liquid is 4 ~ 5, needs PH to be adjusted to about 10, adds and a certain amount of Na
2s.
Ensureing that under the prerequisite of Pb, Cd clearance in chemical leaching waste liquid more than 95%, it is as follows that comparative result is sent out in the utility model method and chemical precipitation:
(1) adopt aforesaid method, Pb, Cd content residual in Ethylene recov is 1 ~ 2% of stoste; Adopt chemical precipitation method, Pb, Cd content residual in Ethylene recov is 3 ~ 5% of stoste.
(2) NaOH dosage, adopts aforesaid method comparatively chemical precipitation method few more than 75%.
(3) Na
2s dosage, adopts aforesaid method comparatively chemical precipitation method few more than 20%.
(4) aforesaid method is adopted, the acid solution of recyclable more than 75%; And adopt chemical precipitation method, cannot acid solution be reclaimed.
(5) aforesaid method is adopted, the Na of recyclable more than 80%
2eDTA; And adopt chemical precipitation method, the Na of 60 ~ 75% can only be reclaimed
2eDTA.
The content that above-described embodiment is illustrated should be understood to these embodiments only for being illustrated more clearly in the utility model, and be not used in restriction scope of the present utility model, after having read the utility model, the amendment of those skilled in the art to the various equivalent form of value of the present utility model has all fallen within the application's claims limited range.