CN111056653A - Cold rolling wastewater treatment system and method - Google Patents
Cold rolling wastewater treatment system and method Download PDFInfo
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- CN111056653A CN111056653A CN201911280454.8A CN201911280454A CN111056653A CN 111056653 A CN111056653 A CN 111056653A CN 201911280454 A CN201911280454 A CN 201911280454A CN 111056653 A CN111056653 A CN 111056653A
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- 238000004065 wastewater treatment Methods 0.000 title claims abstract description 35
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/24—Treatment of water, waste water, or sewage by flotation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5281—Installations for water purification using chemical agents
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/16—Nature of the water, waste water, sewage or sludge to be treated from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
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Abstract
The invention discloses a cold rolling wastewater treatment system and a method thereof, wherein the method comprises the steps of sequentially treating acid-containing wastewater of a cold rolling production line by an acid-containing wastewater pretreatment unit, filtering by an ultrafiltration membrane and filtering by a reverse osmosis membrane to obtain desalted water; in the ultrafiltration membrane filtration, the operation pressure is 0.1-0.5 MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 mu m; in the reverse osmosis membrane filtration, the operating pressure is 3-6 MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm; treating the alkali-containing wastewater of the cold rolling production line by an alkali-containing wastewater pretreatment unit to obtain first return water; treating the wastewater containing the concentrated oil and the emulsion in the cold rolling production line by a concentrated oil and emulsion wastewater treatment unit to obtain second backwater; and mixing the desalted water, the first return water and the second return water to obtain reuse water. The reuse water is directly reused to the cold rolling circulating water system, so that the problem that cold rolling waste water is difficult to recycle is solved, and zero discharge of the cold rolling waste water is realized.
Description
Technical Field
The invention belongs to the technical field of metallurgical environmental protection, and particularly relates to a cold rolling wastewater treatment system and a method thereof.
Background
Cold rolling is used as a deep processing industry in the steel industry, the water consumption is large, and various waste water is generated in the production process, including waste acid, waste alkali waste water, waste water containing oil and emulsion. The cold rolling waste water has very complex components, and besides acid, alkali, oil, emulsion and a small amount of mechanical impurities, the cold rolling waste water also contains a large amount of metal salts, wherein the iron salts are the most main, and in addition, a small amount of heavy metal ions and organic compounds are contained.
With the continuous improvement of steel rolling capacity in China, the waste water amount of cold rolling waste waterAlso improves year by year, and the water quality of the waste water changes greatly. At present, cold rolling wastewater can meet the discharge requirement after being treated, at present, three types of wastewater generated in the cold rolling production process are respectively treated and then directly mixed and discharged, and the Ca content is caused after the acid-containing wastewater is treated2+And Cl-The content is extremely high, the recycling causes serious scaling and corrosion problems of equipment, and the service life of the equipment is seriously shortened.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a system and a method for treating cold rolling wastewater, which aim to solve the problem of low cyclic utilization rate of the cold rolling wastewater in the prior art.
The invention realizes the purpose through the following technical scheme:
in one aspect, the present invention provides a cold rolling wastewater treatment method, comprising,
sequentially treating acid-containing wastewater of a cold rolling production line by an acid-containing wastewater pretreatment unit, filtering by an ultrafiltration membrane and filtering by a reverse osmosis membrane to obtain desalted water; in the ultrafiltration membrane filtration, the operation pressure is 0.1-0.5 MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 mu m; in the reverse osmosis membrane filtration, the operating pressure is 3-6 MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
treating the alkali-containing wastewater of the cold rolling production line by an alkali-containing wastewater pretreatment unit to obtain first return water;
treating the wastewater containing the concentrated oil and the emulsion in the cold rolling production line by a concentrated oil and emulsion wastewater treatment unit to obtain second backwater;
and mixing the desalted water, the first return water and the second return water to obtain reuse water.
Further, in the reuse water, the weight ratio of the weight of the desalted water to the total weight of the first return water and the second return water is 1: (0.5 to 3).
Further, the acid-containing wastewater of the cold rolling production line is sequentially treated by an acid-containing wastewater pretreatment unit, filtered by an ultrafiltration membrane and filtered by a reverse osmosis membrane to obtain desalted water, which comprises,
mixing acid-containing wastewater of a cold rolling production line with alkali liquor, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water; the preset value is 7-9.
Further, the alkali liquor is calcium hydroxide solution and sodium hydroxide solution.
Further, the alkali-containing wastewater of the cold rolling production line is treated by an alkali-containing wastewater pretreatment unit to obtain first return water, comprising,
adjusting the pH value of alkali-containing wastewater of a cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first return water, wherein the preset value is 7-9, and the cooling temperature is 30-40 ℃.
Further, the wastewater containing the thick oil and the emulsion of the cold rolling production line is treated by a wastewater treatment unit containing the thick oil and the emulsion to obtain second backwater, which comprises,
and sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water, wherein the cooling temperature is 30-40 ℃.
In another aspect, the present invention provides a system for a cold rolling wastewater treatment method as described above, the system comprising,
an acid-containing wastewater pretreatment unit, a UF + RO double-membrane treatment unit, an alkali-containing wastewater pretreatment unit, a concentrated oil and emulsion-containing wastewater pretreatment unit and a blending tank,
the UF + RO double-membrane treatment unit is provided with an ultrafiltration membrane and a reverse osmosis membrane,
the water outlet of the acid-containing wastewater pretreatment unit is communicated with the water inlet of the UF + RO double-membrane treatment unit, and the water outlet of the UF + RO double-membrane treatment unit is communicated with the inlet of the blending tank;
the water outlet of the alkali-containing wastewater pretreatment unit is communicated with the inlet of the blending tank;
the water outlet of the concentrated oil and emulsion containing wastewater pretreatment unit is communicated with the inlet of the blending tank;
and the outlet of the blending pool is communicated with the inlet of a water system of the cold rolling production line.
Further, the acid-containing wastewater pretreatment unit comprises a first regulating tank, a primary neutralization tank, a secondary neutralization tank, a reaction clarification tank, a sand filter and a first pH regulating tank,
the water outlet of the first regulating tank is communicated with the water inlet of the primary neutralization tank, the water outlet of the primary neutralization tank is communicated with the water inlet of the secondary neutralization tank, the water outlet of the secondary neutralization tank is communicated with the water inlet of the reaction clarification tank, the water outlet of the reaction clarification tank is communicated with the water inlet of the sand filter, the water outlet of the sand filter is communicated with the inlet of the first pH regulating tank, and the water outlet of the first pH regulating tank is communicated with the water inlet of the UF + RO double-membrane treatment unit.
Further, the alkali-containing wastewater pretreatment unit comprises a second adjusting tank, a second pH adjusting tank, a coagulation tank, an air floatation tank, a first cooling tower, a contact biological oxidation tank and a secondary sedimentation tank,
the water outlet of the second adjusting tank is communicated with the water inlet of the second pH adjusting tank, the water outlet of the second pH adjusting tank is communicated with the water inlet of the coagulation tank, the water outlet of the coagulation tank is communicated with the water inlet of the air floatation tank, the water outlet of the air floatation tank is communicated with the water inlet of the cooling tower, the water outlet of the cooling tower is communicated with the water inlet of the contact biological oxidation tank, the water outlet of the contact biological oxidation tank is communicated with the water inlet of the secondary sedimentation tank, and the water outlet of the secondary sedimentation tank is communicated with the water inlet of the blending tank.
Further, the pretreatment unit for the wastewater containing the thick oil and the emulsion comprises a third regulating tank, a paper bag filter, an ultrafiltration component, a second cooling tower, an aeration tank and a membrane bioreactor,
the water outlet of the third regulating tank is communicated with the water inlet of the paper bag filter, the water outlet of the paper bag filter is communicated with the water inlet of the ultrafiltration component, the water outlet of the ultrafiltration component is communicated with the water inlet of the second cooling tower, the water outlet of the second cooling tower is communicated with the water inlet of the aeration tank, the water outlet of the aeration tank is communicated with the water inlet of the membrane bioreactor, and the water outlet of the membrane bioreactor is communicated with the blending tank.
The beneficial effects of the invention at least comprise:
the invention discloses a cold rolling wastewater treatment system and a method thereof, wherein the method comprises the steps of sequentially treating acid-containing wastewater of a cold rolling production line by an acid-containing wastewater pretreatment unit, filtering by an ultrafiltration membrane and filtering by a reverse osmosis membrane to obtain desalted water; in the ultrafiltration membrane filtration, the operation pressure is 0.1-0.5 MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 mu m; in the reverse osmosis membrane filtration, the operating pressure is 3-6 MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm; treating the alkali-containing wastewater of the cold rolling production line by an alkali-containing wastewater pretreatment unit to obtain first return water; treating the wastewater containing the concentrated oil and the emulsion in the cold rolling production line by a concentrated oil and emulsion wastewater treatment unit to obtain second backwater; and mixing the desalted water, the first return water and the second return water to obtain reuse water. The method comprises the steps of pretreating acid-containing wastewater generated by cold rolling, filtering with an ultrafiltration membrane and filtering with reverse osmosis, removing acid and suspended matters in the acid-containing wastewater by pretreatment, intercepting colloid, protein, microorganisms and macromolecular organic matters in the wastewater under specific ultrafiltration membrane operating pressure and specific filter diameter, and intercepting dissolved salts including Ca under specific reverse osmosis membrane operating pressure and specific filter diameter2+And Cl-And organic substances with molecular weight more than 100 are intercepted, and water molecules can pass through, so that the conductivity of the desalted water is low, and Cl is contained-The content is low and the total iron content is zero, and the obtained reclaimed water and the Ca-containing reclaimed water are mixed with the alkali-containing wastewater, the concentrated oil-containing wastewater and the emulsified liquid wastewater which are respectively treated in a blending tank to obtain the reclaimed water and the Ca-containing reclaimed water2+And Cl-The content is low, the scale formation and corrosion problems are not easy to occur when the cold rolling waste water is directly recycled to a cold rolling system, the treatment and recycling problems of cold rolling waste water are solved, and zero discharge is realized.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic view of a cold rolling wastewater treatment system according to an embodiment of the present invention;
FIG. 2 is a process step diagram of a cold rolling wastewater treatment method according to an embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the technical scheme in the embodiment of the invention has the following general idea:
in one aspect, the present invention provides a cold rolling wastewater treatment system, fig. 1 is a schematic view of a cold rolling wastewater treatment system according to an embodiment of the present invention, and in conjunction with fig. 1, the system includes,
the system comprises an acid-containing wastewater pretreatment unit, a UF + RO double-membrane treatment unit, an alkali-containing wastewater pretreatment unit, a concentrated oil and emulsion-containing wastewater pretreatment unit and a blending pool, wherein the UF + RO double-membrane treatment unit is provided with an ultrafiltration membrane and a reverse osmosis membrane, the water outlet of the acid-containing wastewater pretreatment unit is communicated with the water inlet of the UF + RO double-membrane treatment unit, and the water outlet of the UF + RO double-membrane treatment unit is communicated with the inlet of the blending pool; the water outlet of the alkali-containing wastewater pretreatment unit is communicated with the inlet of the blending tank; the water outlet of the concentrated oil and emulsion containing wastewater pretreatment unit is communicated with the inlet of the blending tank; and the outlet of the blending pool is communicated with the inlet of a water system of the cold rolling production line.
The method comprises the steps of pretreating acid-containing wastewater generated by cold rolling, filtering with an ultrafiltration membrane and filtering with reverse osmosis, removing acid and suspended matters in the acid-containing wastewater by pretreatment, intercepting colloid, protein, microorganisms and macromolecular organic matters in the wastewater under the specific ultrafiltration membrane operation pressure and filtration diameter, intercepting dissolved salt and organic matters with molecular weight more than 100 under the specific reverse osmosis membrane operation pressure and filtration diameter, and allowing water molecules to pass through, so that the conductivity of desalted water is low, and Cl is low-The method has the advantages that the content is low, the total iron content is zero, the alkali-containing wastewater, the concentrated oil-containing wastewater and the emulsion wastewater which are respectively treated are mixed in a blending tank, the obtained reuse water has extremely low salt content, the scale formation phenomenon can not occur when the reuse water is directly reused in a cold rolling system, the problems of treatment and recycling of the cold rolling wastewater are solved, and zero emission is realized.
Further, the acid-containing wastewater pretreatment unit comprises a first regulating tank, a primary neutralization tank, a secondary neutralization tank, a reaction clarification tank, a sand filter and a first pH regulating tank, wherein a water outlet of the first regulating tank is communicated with a water inlet of the primary neutralization tank, a water outlet of the primary neutralization tank is communicated with a water inlet of the secondary neutralization tank, a water outlet of the secondary neutralization tank is communicated with a water inlet of the reaction clarification tank, a water outlet of the reaction clarification tank is communicated with a water inlet of the sand filter, a water outlet of the sand filter is communicated with an inlet of the first pH regulating tank, and a water outlet of the first pH regulating tank is communicated with a water inlet of the UF + RO double-membrane treatment unit.
The acid-containing wastewater contains hydrochloric acid and Fe2+The first regulating reservoir is used for regulating the water quantity of the acid-containing wastewater and balancing the water quality, the pump pumps the acid-containing wastewater in the first regulating reservoir into a primary neutralization pond, the primary neutralization pond and a secondary neutralization pond are connected in series, the acid-containing wastewater is aerated in the primary neutralization pond and the secondary neutralization pond, and the acid-containing wastewater is aerated in the primary neutralization pond and the secondary neutralization pondAnd reacting with calcium hydroxide or sodium hydroxide in the secondary neutralization pond to convert Fe2+ ions in the acid-containing wastewater into precipitable metal hydroxide. The first-stage neutralization tank and the second-stage neutralization tank are also provided with a dosing system and a pH detection device, raw calcium hydroxide solution or sodium hydroxide solution is added through the dosing system, the pH detection device is adopted to detect the pH value of the wastewater in the first-stage neutralization tank and the second-stage neutralization tank, and whether the acid in the wastewater is completely neutralized or not is judged, and Fe2+Whether all have been converted to metal hydroxide precipitates. The reaction clarification tank can remove metal hydroxides in the primary neutralization tank and the secondary neutralization tank, the reaction clarification tank comprises a reaction zone and a settling zone, and a flocculating agent and a coagulant aid can be added into the acid-containing wastewater treated by the secondary neutralization tank before the acid-containing wastewater enters the settling zone, so that the settling efficiency of the metal hydroxides is improved; the sand filter is used for filtering acid-containing wastewater treated by the reaction clarification tank to remove suspended matters, sand filtered water enters the first pH adjusting tank and is mixed with hydrochloric acid to adjust the pH value, the adjusted pH value is 7-9, and the purpose of adjusting the pH value is to meet the requirement of ultrafiltration influent water quality. The effluent conductivity of the first pH adjusting tank is less than 15000 mu S/cm, and Cl is-Less than 3000mg/L, pH value of 7-9, total iron less than 0.5mg/L and turbidity less than 20 NTU.
Further, the alkali-containing wastewater pretreatment unit comprises a second adjusting tank, a second pH adjusting tank, a coagulation tank, an air flotation tank, a first cooling tower, a contact biological oxidation tank and a secondary sedimentation tank, wherein a water outlet of the second adjusting tank is communicated with a water inlet of the second pH adjusting tank, a water outlet of the second pH adjusting tank is communicated with a water inlet of the coagulation tank, a water outlet of the coagulation tank is communicated with a water inlet of the air flotation tank, a water outlet of the air flotation tank is communicated with a water inlet of the cooling tower, a water outlet of the cooling tower is communicated with a water inlet of the contact biological oxidation tank, a water outlet of the contact biological oxidation tank is communicated with a water inlet of the secondary sedimentation tank, and a water outlet of the secondary sedimentation tank is communicated with a water inlet of the blending tank.
The alkali-containing wastewater contains substances such as oil, alkali (NaOH) and the like, the alkali-containing wastewater enters a second regulating tank for water quantity regulation and water quality balance, the alkali-containing wastewater after the water quantity regulation and the water quality balance enters a second pH regulating tank, acid liquor (hydrochloric acid or sulfuric acid) is added into the second pH regulating tank for pH regulation so as to neutralize sodium hydroxide in the alkali-containing wastewater, and the pH value after the regulation is 7-9. And (3) feeding the alkali-containing wastewater after pH adjustment into a coagulation tank, and adding a flocculating agent into the coagulation tank to enable oil and suspended matter particles in the alkali-containing wastewater to form larger flocs. The air floatation tank is used for separating suspended matters, oil and the like in the flocculated alkali-containing wastewater to the water surface to form air floating slag and removing the air floating slag to obtain air floating liquid. The air flotation liquid enters a cooling tower, the temperature of the alkali-containing wastewater for cleaning the strip steel is high due to the high temperature of the strip steel of the cold rolling production line, the temperature of the air flotation liquid is 50-60 ℃, the air flotation liquid is cooled to 30-40 ℃ by the cooling tower, if the temperature is not cooled, the temperature is too high, the microorganisms in the contact biological oxidation tank can be killed, and the cooled air flotation liquid enters the contact biological oxidation tank to carry out biochemical reaction with the microorganisms, so that the residual COD is further removed. The effluent of the contact biological oxidation tank contains a large amount of suspended matters formed by microorganism corpses, the suspended matters can be settled and removed after entering a secondary sedimentation tank, and the effluent of the secondary sedimentation tank is subjected to sand filtration to obtain first return water.
Further, the pretreatment unit for wastewater containing concentrated oil and emulsion comprises a third regulating tank, a paper bag filter, an ultrafiltration component, a second cooling tower, an aeration tank and a membrane bioreactor, wherein a water outlet of the third regulating tank is communicated with a water inlet of the paper bag filter, a water outlet of the paper bag filter is communicated with a water inlet of the ultrafiltration component, a water outlet of the ultrafiltration component is communicated with a water inlet of the second cooling tower, a water outlet of the second cooling tower is communicated with a water inlet of the aeration tank, a water outlet of the aeration tank is communicated with a water inlet of the membrane bioreactor, and a water outlet of the membrane bioreactor is communicated with the blending tank.
The wastewater containing the concentrated oil and the emulsion contains oil, emulsion, alkali (NaOH), a cleaning agent, a surface agent and the like, and the wastewater containing the concentrated oil and the emulsion enters a third regulating tank for water quantity regulation and water quality balance; and (4) allowing the wastewater containing the thick oil and the emulsion after the treatment in the third regulating tank to enter a paper bag filter, and removing large-particle oil and coarse floating slag in the wastewater containing the thick oil and the emulsion to obtain the effluent of the paper bag filter. The waste water containing the concentrated oil and the emulsion treated by the paper bag filter enters an ultrafiltration component to remove small-particle oil in the waste water, and the effluent water is subjected to oil-water separation through the interception effect of an ultrafiltration membrane. The wastewater containing the concentrated oil and the emulsion after being filtered by the ultrafiltration component enters a second cooling tower for cooling, so that the temperature of the wastewater is suitable for the biochemical reaction of microorganisms in the aeration tank, and the effluent of the second cooling tower is obtained, wherein the temperature of the effluent of the second cooling tower is 30-40 ℃; and the effluent of the second cooling tower enters a membrane bioreactor to generate biochemical action with microorganisms, the COD in the effluent of the second cooling tower is removed, and meanwhile, the effluent is filtered to obtain second return water.
In another aspect, the embodiment of the present invention provides a method for treating cold rolling wastewater by using the above-mentioned cold rolling wastewater treatment system, fig. 2 is a process step diagram of a cold rolling wastewater treatment method according to the embodiment of the present invention, and with reference to fig. 2, the method comprises,
s1, sequentially treating the acid-containing wastewater of the cold rolling production line by an acid-containing wastewater pretreatment unit, filtering by an ultrafiltration membrane and filtering by a reverse osmosis membrane to obtain desalted water; treating the alkali-containing wastewater of the cold rolling production line by an alkali-containing wastewater pretreatment unit to obtain first return water; and treating the wastewater containing the concentrated oil and the emulsion in the cold rolling production line by a concentrated oil and emulsion wastewater treatment unit to obtain second backwater.
The method comprises the following steps:
mixing acid-containing wastewater of a cold rolling production line with alkali liquor, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water.
Further, the preset value is 7-9.
Further, in the ultrafiltration membrane filtration, the operation pressure is 0.1-0.5 MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 mu m; in the reverse osmosis membrane filtration, the operating pressure is 3-6 MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
the UF + RO double-membrane treatment unit is provided with an ultrafiltration membrane and a reverse osmosis membrane, wherein the ultrafiltration membrane and the reverse osmosis membrane are used for dissolving and quantifying solute under the action of pressure and can permeate the membrane, and the rest components are intercepted.
The ultrafiltration membrane allows small molecular substances, soluble solids (inorganic salts) and the like to pass through, and simultaneously retains colloids, proteins, microorganisms and macromolecular organic matters with the diameter of 0.002-0.1 micron, and the cut molecular weight for representing the pore size of the ultrafiltration membrane is generally in the range of 1000-500000. The ultrafiltration membrane has the following requirements on the quality of inlet water, wherein the turbidity is less than 50NTU, the suspended matters are less than 100mg/L, the temperature is 5-45 ℃, and the PH value is 2-13.
Reverse osmosis membranes are the finest of the membrane separation products that are effective in retaining the components including Ca2+And Cl-All dissolved salts and organic substances with molecular weight more than 100 in the water, and water molecules are allowed to pass through. Reverse osmosis has a high requirement for influent water, wherein turbidity is present<1NTU，SDI15<5, total iron<50ug/L, pH 3-10, and temperature 5-45 deg.C.
The desalting rate of the effluent can exceed 99 percent through ultrafiltration membrane filtration and reverse osmosis filtration.
The conductivity of the desalted water is less than 100 mu S/cm, Cl-Less than 50mg/L, pH 7-8, total iron about 0mg/L, turbidity about 0 NTU. The strong brine intercepted by filtration can be used for dust suppression in stock yards and absorption of sintered mixed materials.
Further, the alkali liquor is calcium hydroxide solution or sodium hydroxide solution. Calcium hydroxide solution is often used in actual industrial production because calcium hydroxide has the advantage of low cost and is helpful for flocculation precipitation, but calcium hydroxide introduces calcium ions which are easy to scale, and the introduced calcium ions are removed by reverse osmosis filtration. The sodium hydroxide solution is adopted, so that the introduction of scaling ions is avoided, but the price is high, and the application in enterprise production is less.
Adjusting the pH value of the alkali-containing wastewater of the cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first backwater. The conductivity of the first return water is less than 3000 mu S/cm, and Cl-Is less than 500mg/L, the PH value is 7-9, the total iron is less than 0.5mg/L, and the turbidity is less than 20 NTU.
Further, the preset value is 7-9.
Further, the cooling temperature is 30-40 ℃.
And sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water. The conductivity of the second return water is less than 3000 mu S/cm, and Cl-Is less than 500mg/L, the PH value is 7-9, the total iron is less than 0.5mg/L, and the turbidity is less than 20 NTU.
Further, the cooling temperature is 30-40 ℃.
And S2, mixing the desalted water, the first return water and the second return water to obtain reuse water. The conductivity of the reuse water is less than 1000 mu S/cm, and Cl-Less than 250mg/L, the pH value of 7-9, the total iron content of less than 0.3mg/L and the turbidity of less than 10 NTU.
Further, in the reuse water, the weight ratio of the desalted water to the sum of the weights of the first return water and the second return water is 1: (0.5 to 3).
The invention discloses a cold rolling wastewater treatment system and a method thereof, wherein acid-containing wastewater, alkali-containing wastewater, concentrated oil-containing wastewater and emulsion wastewater generated by cold rolling are respectively treated and then mixed in a blending tank to obtain reuse water, the reuse water has low conductivity and low salt content, is used for a cold rolling system, is not easy to cause scaling and corrosion problems, realizes the treatment and cyclic utilization of the cold rolling wastewater, realizes zero discharge, reduces the sewage discharge and industrial new water purchase of an iron and steel plant, reduces the competition of the iron and steel plant on fresh water resources in peripheral areas, and effectively protects the water environment in the peripheral areas. The method is used for respectively treating the acid-containing wastewater, the alkali-containing wastewater and the wastewater containing the concentrated oil and the emulsion generated by the cold rolling production line, has strong pertinence, lightens the impact on a wastewater treatment system due to the drastic change of water quality, and has the advantages of stable operation of the wastewater treatment system, guaranteed quality of effluent water and high wastewater treatment efficiency. After the acid-containing wastewater is pretreated, the acid-containing wastewater is subjected to UF + RO advanced treatment, so that the quality of the desalted water is further improved.
The technical solution of the present invention will be further described with reference to specific examples.
Example 1
Example 1 provides a method for treating cold rolling wastewater, which comprises,
s1, respectively treating the acid-containing wastewater, the alkali-containing wastewater and the wastewater containing the concentrated oil and the emulsion generated in the cold rolling production line to obtain desalted water, first backwater and second backwater. The method comprises the following steps:
mixing acid-containing wastewater of a cold rolling production line with calcium hydroxide, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water. The index of the desalted water is shown in Table 1.
Further, the preset value is 7.
Further, in the ultrafiltration membrane filtration, the operation pressure is 0.2MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 μm; in the reverse osmosis membrane filtration, the operating pressure is 3MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
the water inlet quality of the ultrafiltration membrane is turbidity 45NTU, suspended substance 90mg/L, temperature 35 ℃, and PH value 7.
The inlet water quality of the reverse osmosis membrane is as follows: turbidity was 0.8NTU, SDI15 was 4, total iron was 29ug/L, pH 7, temperature was 35 ℃.
Adjusting the pH value of the alkali-containing wastewater of the cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first backwater. The index of the first return water is shown in table 2.
Further, the preset value is 8.
Further, the cooling temperature was 35 ℃.
And sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water. The index of the second return water is shown in table 3.
Further, the cooling temperature was 35 ℃.
And S2, mixing the desalted water, the first return water and the second return water to obtain reuse water. The index of reuse water is shown in Table 4.
Further, in the reuse water, the weight ratio of the desalted water to the sum of the weights of the first return water and the second return water is 1: 1.
example 2
Example 2 provides a method for treating cold rolling wastewater, the method comprising,
s1, respectively treating the acid-containing wastewater, the alkali-containing wastewater and the wastewater containing the concentrated oil and the emulsion generated in the cold rolling production line to obtain desalted water, first backwater and second backwater. The method comprises the following steps:
mixing acid-containing wastewater of a cold rolling production line with sodium hydroxide, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water. The index of the desalted water is shown in Table 1.
Further, the preset value is 8.
Further, in the ultrafiltration membrane filtration, the operation pressure is 0.4MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 μm; in the reverse osmosis membrane filtration, the operating pressure is 6MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
the water inlet quality of the ultrafiltration membrane is turbidity 40NTU, suspended substance 95mg/L, temperature 35 ℃, and PH value 6.
The inlet water quality of the reverse osmosis membrane is as follows: turbidity was 0.9NTU, SDI15 was 4.5, total iron was 32ug/L, pH 6, temperature was 35 ℃.
Adjusting the pH value of the alkali-containing wastewater of the cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first backwater. The index of the first return water is shown in table 2.
Further, the preset value is 9.
Further, the cooling temperature was 35 ℃.
And sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water. The index of the second return water is shown in table 3.
Further, the cooling temperature was 35 ℃.
And S2, mixing the desalted water, the first return water and the second return water to obtain reuse water. The index of reuse water is shown in Table 4.
Further, in the reuse water, the weight ratio of the desalted water to the sum of the weights of the first return water and the second return water is 1: 2.8.
example 3
Example 3 provides a method for treating cold rolling wastewater, the method comprising,
s1, respectively treating the acid-containing wastewater, the alkali-containing wastewater and the wastewater containing the concentrated oil and the emulsion generated in the cold rolling production line to obtain desalted water, first backwater and second backwater. The method comprises the following steps:
mixing acid-containing wastewater of a cold rolling production line with calcium hydroxide, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water. The index of the desalted water is shown in Table 1.
Further, the preset value is 9.
Further, in the ultrafiltration membrane filtration, the operation pressure is 0.5MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 μm; in the reverse osmosis membrane filtration, the operating pressure is 5MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
the water inlet quality of the ultrafiltration membrane is turbidity 39NTU, suspended substance 85mg/L, temperature 25 ℃, and PH value 3.
The inlet water quality of the reverse osmosis membrane is as follows: turbidity was 0.6NTU, SDI15 was 4.5, total iron was 42ug/L, pH was 3, temperature was 25 ℃.
Adjusting the pH value of the alkali-containing wastewater of the cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first backwater. The index of the first return water is shown in table 2.
Further, the preset value is 7.
Further, the cooling temperature was 31 ℃.
And sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water. The index of the second return water is shown in table 3.
Further, the cooling temperature was 31 ℃.
And S2, mixing the desalted water, the first return water and the second return water to obtain reuse water. The index of reuse water is shown in Table 4.
Further, in the reuse water, the weight ratio of the desalted water to the sum of the weights of the first return water and the second return water is 1: 0.8.
example 4
Example 4 provides a method for treating cold rolling wastewater, the method comprising,
s1, respectively treating the acid-containing wastewater, the alkali-containing wastewater and the wastewater containing the concentrated oil and the emulsion generated in the cold rolling production line to obtain desalted water, first backwater and second backwater. The method comprises the following steps:
mixing acid-containing wastewater of a cold rolling production line with sodium hydroxide, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water. The index of the desalted water is shown in Table 1.
Further, the preset value is 9.
Further, in the ultrafiltration membrane filtration, the operation pressure is 0.1MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 μm; in the reverse osmosis membrane filtration, the operating pressure is 6MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
the inlet water quality of the ultrafiltration membrane is 44NTU turbidity, 88mg/L suspended substance, 15 ℃ temperature and 3 PH value.
The inlet water quality of the reverse osmosis membrane is as follows: turbidity was 0.9NTU, SDI15 was 4.5, total iron was 46ug/L, pH was 3, temperature was 15 ℃.
Adjusting the pH value of the alkali-containing wastewater of the cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first backwater. The index of the first return water is shown in table 2.
Further, the preset value is 7.5.
Further, the cooling temperature was 39 ℃.
And sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water. The index of the second return water is shown in table 3.
Further, the cooling temperature was 39 ℃.
And S2, mixing the desalted water, the first return water and the second return water to obtain reuse water. The index of reuse water is shown in Table 4.
Further, in the reuse water, the weight ratio of the desalted water to the sum of the weights of the first return water and the second return water is 1: 2.7.
comparative example 1
Comparative example 1 is that in the prior art, acid-containing wastewater from a cold rolling production line is mixed with sodium hydroxide, and then sequentially filtered, adjusted to a preset pH value, and discharged.
Comparative example 2
Comparative example 2 is the prior art that the alkali-containing wastewater from the cold rolling production line is sequentially subjected to pH value adjustment to a preset value, flocculation, air floatation scum removal, cooling, biochemical reaction and precipitation for discharge.
Comparative example 3
Comparative example 3 is the prior art in which the waste water containing oil and emulsion from the cold rolling line is sequentially subjected to primary filtration, secondary filtration, cooling, biochemical reaction and filtration, and then discharged.
TABLE 1
| Item | Conductivity,. mu.S/cm | Cl-，mg/L | pH value | Total iron, mg/L | Turbidity, NTU |
| Example 1 | 92 | 21 | 7.3 | 0 | 0 |
| Example 2 | 74 | 15 | 7.1 | 0 | 0 |
| Example 3 | 49 | 11 | 7.2 | 0 | 0 |
| Example 4 | 28 | 6 | 7.1 | 0 | 0 |
| Comparative example 1 | 8384 | 1690 | 8.2 | 0.36 | 14 |
TABLE 2
| Item | Conductivity,. mu.S/cm | Cl-，mg/L | pH value | Total iron, mg/L | Turbidity, NTU |
| Example 1 | 2810 | 441 | 7.9 | 0.38 | 13 |
| Example 2 | 2405 | 386 | 8.8 | 0.41 | 15 |
| Example 3 | 1982 | 315 | 7.5 | 0.25 | 8 |
| Example 4 | 1421 | 288 | 8.6 | 0.28 | 12 |
TABLE 3
| Item | Conductivity,. mu.S/cm | Cl-，mg/L | pH value | Total iron, mg/L | Turbidity, NTU |
| Example 1 | 2920 | 445 | 7.6 | 0.41 | 11 |
| Example 2 | 2448 | 395 | 8.2 | 0.26 | 9 |
| Example 3 | 1898 | 331 | 8.4 | 0.37 | 10 |
| Example 4 | 1396 | 276 | 7.8 | 0.11 | 15 |
TABLE 4
| Item | Conductivity,. mu.S/cm | Cl-，mg/L | pH value | Total iron, mg/L | Turbidity, NTU |
| Example 1 | 991 | 155 | 7.2 | 0.14 | 5 |
| Examples2 | 998 | 176 | 7.4 | 0.21 | 6 |
| Example 3 | 974 | 186 | 7.5 | 0.18 | 8 |
| Example 4 | 996 | 207 | 7.8 | 0.25 | 10 |
| Comparative example 1 | 8384 | 1690 | 8.2 | 0.36 | 14 |
| Comparative example 2 | 1902 | 293 | 7.5 | 0.31 | 9 |
| Comparative example 3 | 1889 | 313 | 8.4 | 0.36 | 11 |
The indexes of the desalted water of examples 1 to 4 and the discharge water treated in comparative example 1 are shown in Table 1, and it can be seen from the data in Table 1 that the conductivity of examples 1 to 4 is 28 to 92S/cm, Cl is shown in examples 1 to 4-6-21 mg/L, zero total iron and zero turbidity. Comparative example 1 discharge Water conductivity 8384S/cm, Cl-1690mg/L, total iron 0.36, turbidity 14. Compared with comparative example 1, the acid-containing wastewater of the invention has the conductivity and Cl after being treated-The content is greatly reduced.
Table 4 shows the indexes of the reuse water obtained by the wastewater treatment of examples 1 to 4 and the effluent water obtained by the treatment of comparative examples 1 to 3, and it can be seen from the data in Table 4 that the conductivity of examples 1 to 4 is 991 to 996. mu.S/cm, Cl-155-207 mg/L, and 0.14-0.25 mg/L total iron. Comparative examples 1 to 3, which have conductivities of 1889 to 8384 and Cl-293-1690 mg/L, total iron 0.31-0.36 mg/L. Conductivity, Cl, of examples 1 to 4 compared to comparative examples 1 to 3-The content and total iron content are lower, and the water quality indexes of the embodiments 1 to 4 meet the specified requirements of reclaimed water quality index for circulating cooling water, and can be reused as reclaimed water.
It should be noted that the conductivity can be used to characterize the salt content of the liquid.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A cold rolling wastewater treatment method is characterized by comprising the following steps,
sequentially treating acid-containing wastewater of a cold rolling production line by an acid-containing wastewater pretreatment unit, filtering by an ultrafiltration membrane and filtering by a reverse osmosis membrane to obtain desalted water; in the ultrafiltration membrane filtration, the operation pressure is 0.1-0.5 MPa, and the filter diameter of the ultrafiltration membrane is 0.01-0.1 mu m; in the reverse osmosis membrane filtration, the operating pressure is 3-6 MPa, and the filter diameter of the reverse osmosis membrane is 0.1-1 nm;
treating the alkali-containing wastewater of the cold rolling production line by an alkali-containing wastewater pretreatment unit to obtain first return water;
treating the wastewater containing the concentrated oil and the emulsion in the cold rolling production line by a concentrated oil and emulsion wastewater treatment unit to obtain second backwater;
and mixing the desalted water, the first return water and the second return water to obtain reuse water.
2. The cold rolling wastewater treatment method according to claim 1, wherein the weight ratio of the demineralized water to the total weight of the first return water and the second return water in the reuse water is 1: (0.5 to 3).
3. The cold rolling wastewater treatment method according to claim 1, wherein the acid-containing wastewater of the cold rolling production line is sequentially subjected to an acid-containing wastewater pretreatment unit, ultrafiltration membrane filtration and reverse osmosis membrane filtration to obtain desalted water, comprising,
mixing acid-containing wastewater of a cold rolling production line with alkali liquor, sequentially filtering, adjusting the pH value to a preset value, filtering with an ultrafiltration membrane and filtering with a reverse osmosis membrane to obtain desalted water; the preset value is 7-9.
4. The cold rolling wastewater treatment method according to claim 3, wherein the alkali solution is calcium hydroxide solution and sodium hydroxide solution.
5. The cold rolling wastewater treatment method according to claim 1, wherein the alkali-containing wastewater of the cold rolling line is treated by an alkali-containing wastewater pretreatment unit to obtain a first return water, comprising,
adjusting the pH value of alkali-containing wastewater of a cold rolling production line to a preset value, flocculating, air floating to remove scum, cooling, performing biochemical reaction and precipitating to obtain first return water, wherein the preset value is 7-9, and the cooling temperature is 30-40 ℃.
6. The cold rolling wastewater treatment method according to claim 1, wherein the wastewater containing the concentrated oil and the emulsion in the cold rolling production line is treated by a concentrated oil and emulsion wastewater treatment unit to obtain a second backwater, comprising,
and sequentially carrying out primary filtration, secondary filtration, cooling, biochemical reaction and filtration on the waste water containing the concentrated oil and the emulsion in the cold rolling production line to obtain second return water, wherein the cooling temperature is 30-40 ℃.
7. The system for a cold rolling wastewater treatment method according to any one of claims 1 to 6, comprising,
an acid-containing wastewater pretreatment unit, a UF + RO double-membrane treatment unit, an alkali-containing wastewater pretreatment unit, a concentrated oil and emulsion-containing wastewater pretreatment unit and a blending tank,
the UF + RO double-membrane treatment unit is provided with an ultrafiltration membrane and a reverse osmosis membrane,
the water outlet of the acid-containing wastewater pretreatment unit is communicated with the water inlet of the UF + RO double-membrane treatment unit, and the water outlet of the UF + RO double-membrane treatment unit is communicated with the inlet of the blending tank;
the water outlet of the alkali-containing wastewater pretreatment unit is communicated with the inlet of the blending tank;
the water outlet of the concentrated oil and emulsion containing wastewater pretreatment unit is communicated with the inlet of the blending tank;
and the outlet of the blending pool is communicated with the inlet of a water system of the cold rolling production line.
8. The cold rolling wastewater treatment system of claim 7, wherein the acid-containing wastewater pretreatment unit comprises a first adjusting tank, a primary neutralization tank, a secondary neutralization tank, a reaction clarification tank, a sand filter, a first pH adjusting tank,
the water outlet of the first regulating tank is communicated with the water inlet of the primary neutralization tank, the water outlet of the primary neutralization tank is communicated with the water inlet of the secondary neutralization tank, the water outlet of the secondary neutralization tank is communicated with the water inlet of the reaction clarification tank, the water outlet of the reaction clarification tank is communicated with the water inlet of the sand filter, the water outlet of the sand filter is communicated with the inlet of the first pH regulating tank, and the water outlet of the first pH regulating tank is communicated with the water inlet of the UF + RO double-membrane treatment unit.
9. The cold rolling wastewater treatment system of claim 7, wherein the alkali-containing wastewater pretreatment unit comprises a second adjusting tank, a second pH adjusting tank, a coagulation tank, an air flotation tank, a first cooling tower, a contact biological oxidation tank and a secondary sedimentation tank,
the water outlet of the second adjusting tank is communicated with the water inlet of the second pH adjusting tank, the water outlet of the second pH adjusting tank is communicated with the water inlet of the coagulation tank, the water outlet of the coagulation tank is communicated with the water inlet of the air floatation tank, the water outlet of the air floatation tank is communicated with the water inlet of the cooling tower, the water outlet of the cooling tower is communicated with the water inlet of the contact biological oxidation tank, the water outlet of the contact biological oxidation tank is communicated with the water inlet of the secondary sedimentation tank, and the water outlet of the secondary sedimentation tank is communicated with the water inlet of the blending tank.
10. The cold rolling wastewater treatment system of claim 7, wherein the concentrated oil and emulsion containing wastewater pretreatment unit comprises a third adjusting tank, a paper bag filter, an ultrafiltration module, a second cooling tower, an aeration tank and a membrane bioreactor,
the water outlet of the third regulating tank is communicated with the water inlet of the paper bag filter, the water outlet of the paper bag filter is communicated with the water inlet of the ultrafiltration component, the water outlet of the ultrafiltration component is communicated with the water inlet of the second cooling tower, the water outlet of the second cooling tower is communicated with the water inlet of the aeration tank, the water outlet of the aeration tank is communicated with the water inlet of the membrane bioreactor, and the water outlet of the membrane bioreactor is communicated with the blending tank.
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| CN112266108A (en) * | 2020-11-24 | 2021-01-26 | 江苏科技大学 | Machining emulsified waste liquid treatment device and process based on effective component recovery |
| CN113754187A (en) * | 2021-09-03 | 2021-12-07 | 石横特钢集团有限公司 | Advanced treatment and recycling process for wastewater of iron and steel enterprises |
| CN114368852A (en) * | 2021-12-14 | 2022-04-19 | 唐山钢铁集团有限责任公司 | Cold rolling acid-containing wastewater treatment system and process |
| WO2022078672A1 (en) * | 2020-10-16 | 2022-04-21 | Sms Group Gmbh | Method of treating a cooling circuit water contaminated with organic substances and inorganic particles |
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| WO2022078672A1 (en) * | 2020-10-16 | 2022-04-21 | Sms Group Gmbh | Method of treating a cooling circuit water contaminated with organic substances and inorganic particles |
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| CN114368852B (en) * | 2021-12-14 | 2024-07-02 | 唐山钢铁集团有限责任公司 | Cold rolling acid-containing wastewater treatment system and process |
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Application publication date: 20200424 |