CN110981107A - Silicon steel oil-containing and emulsion wastewater treatment and recycling system and process thereof - Google Patents

Silicon steel oil-containing and emulsion wastewater treatment and recycling system and process thereof Download PDF

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Publication number
CN110981107A
CN110981107A CN201911355911.5A CN201911355911A CN110981107A CN 110981107 A CN110981107 A CN 110981107A CN 201911355911 A CN201911355911 A CN 201911355911A CN 110981107 A CN110981107 A CN 110981107A
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tank
reactor
sludge
wastewater
pipe
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张垒
舒纯
王丽娜
俞琴
刘尚超
刘璞
付本全
卢丽君
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Wuhan Iron and Steel Co Ltd
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Wuhan Iron and Steel Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00Multistage treatment of water, waste water, or sewage
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/02Treatment of water, waste water, or sewage by heating
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/40Devices for separating or removing fatty or oily substances or similar floating material
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/48Treatment of water, waste water, or sewage with magnetic or electric fields
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5281Installations for water purification using chemical agents
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/52Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56Macromolecular compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/66Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F2001/007Processes including a sedimentation step
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/105Phosphorus compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/12Halogens or halogen-containing compounds
    • C02F2101/14Fluorine or fluorine-containing compounds
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    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/30Organic compounds
    • C02F2101/32Hydrocarbons, e.g. oil
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/16Nature 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
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00Controlling or monitoring parameters in water treatment
    • C02F2209/08Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00General aspects of water treatment
    • C02F2301/08Multistage treatments, e.g. repetition of the same process step under different conditions
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/02Aerobic processes
    • C02F3/06Aerobic processes using submerged filters
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/02Aerobic processes
    • C02F3/12Activated sludge processes
    • C02F3/1236Particular type of activated sludge installations
    • C02F3/1268Membrane bioreactor systems
    • C02F3/1273Submerged membrane bioreactors

Abstract

The invention relates to a silicon steel oil and emulsion wastewater treatment and recycling system and a process thereof, which comprises a demulsification regulating reservoir, wherein the demulsification regulating reservoir sequentially comprises a flocculation sedimentation tank, a magnetic flocculation device, a magnetic separation and recovery machine, an ultrafiltration device, a pH regulating tank, a cooling tower, a contact biochemical tank, an MBR (membrane bioreactor) and a clean water tank through a main pipeline; the bottom of the flocculation sedimentation tank is sequentially connected with a sludge concentration tank and a plate-and-frame filter press through pipelines, and the sludge concentration tank is connected with the flocculation sedimentation tank through a supernatant return pipe; the magnetic separation recycling machine is connected with the plate-and-frame filter press through a sludge recycling pipe; the plate-and-frame filter press is communicated with the flocculation sedimentation tank through a filter pressing return pipe; the contact biochemical tank is communicated with the sludge concentration tank through a biochemical sludge pipe. The invention solves the problems of difficult treatment and incapability of recycling the high-concentration organic oily wastewater of the silicon steel oily/emulsified liquid wastewater, realizes zero discharge of the silicon steel oily wastewater and the emulsified liquid wastewater, and saves the investment and the treatment cost of wastewater treatment facilities.

Description

Silicon steel oil-containing and emulsion wastewater treatment and recycling system and process thereof
Technical Field
The invention relates to a wastewater treatment technology, in particular to a silicon steel oil-containing and emulsion wastewater treatment and recycling system and a process thereof.
Background
The silicon steel oily wastewater/emulsion is one of high-concentration refractory wastewater which is difficult to treat at present. The silicon steel oil/emulsion wastewater is the oily wastewater formed by steel enterprises in the process of steel rolling by using emulsified oil as a lubricant and a cooling circulating liquid. The oil-containing wastewater contains petroleum and CODCrThe concentration is very high, the treatment difficulty is large, and the oily and emulsion wastewater in water needs to be treated to reach the second or third standard of the water pollutant discharge table of iron and steel enterprises (GB 13456-2012). The conventional treatment technologies at present comprise a physical method, a chemical method, a physicochemical method and a biological method, namely, the conventional gravity separation, air flotation, chemical flocculation, adsorption, biological treatment, membrane separation, electrolytic oxidation, activated carbon adsorption, integrated combination of the conventional treatment methods and the like. For example, the common silicon steel oily wastewater treatment process adopts an adjusting tank, demulsification and oil removal, coagulating sedimentation, a paper bag filter, a circulating water tank, ultrafiltration membrane separation, an acid-base adjusting tank, a cooling tower, a hydrolysis tank, a contact biological oxidation tank, an MBR reaction tank and active carbon filtrationAnd (4) filtering the filter and finally discharging. The conventional treatment methods have the problems of large occupied area, high treatment cost, large energy consumption, poor adaptability, substandard water quality indexes such as effluent oil, COD and the like, more varieties related to dangerous waste treatment and the like. Therefore, the key for solving the problems at present is to find a silicon steel oil-containing and emulsion wastewater recycling process which is used for treating and transforming silicon steel oil-containing and emulsion wastewater, has low operation cost and stable and up-to-standard water quality.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a silicon steel oil-containing and emulsion wastewater treatment and recycling system and a process thereof.
In order to achieve the purpose, the invention designs a silicon steel oil-containing and emulsion wastewater treatment and recycling system, which comprises a demulsification regulating reservoir, wherein an oil-containing wastewater pipe and a demulsifier pipe are arranged on the side wall of the demulsification regulating reservoir, a heating coil is wound on the outer wall of the demulsification regulating reservoir, and the heating coil is connected with an external waste heat steam pipe; an oil removal recovery device is arranged in the demulsification adjusting tank; the demulsification adjusting tank sequentially comprises a flocculation sedimentation tank, a magnetic flocculation device, a magnetic separation recovery machine, an ultrafiltration device, a pH adjusting tank, a cooling tower, a contact biochemical tank, an MBR (membrane bioreactor) and a clean water tank through a main pipeline; the flocculation sedimentation tank is respectively connected with a flocculant pipe, an alkali solution pipe and a coagulant aid pipe;
the bottom of the flocculation sedimentation tank is sequentially connected with a sludge thickening tank and a plate-and-frame filter press through pipelines, a sludge PAM pipe is arranged on the sludge thickening tank, and the sludge thickening tank is connected with the flocculation sedimentation tank through a supernatant return pipe; the magnetic separation recycling machine is connected with the plate-and-frame filter press through a sludge recycling pipe; the plate-and-frame filter press is communicated with the flocculation sedimentation tank through a filter pressing return pipe; the contact biochemical tank is communicated with the sludge concentration tank through a biochemical sludge pipe; the ultrafiltration device is connected with the demulsification regulating reservoir through a concentrated water return pipe; and an acid liquid pipe is connected to the pH adjusting tank.
Further, the magnetic flocculation device comprises a reactor, wherein the reactor is separated into a reactor I, a reactor II and a reactor III by two partition plates; the height of the isolation plate between the reactor I and the reactor II is lower than the wall body of the reactor; the bottom of the partition plate between the reactor II and the reactor III is communicated, so that the reactor II is communicated with the reactor III; the wall body of the reactor III is provided with a through hole which is communicated with the magnetic flocculation clean water tank; the bottom of the magnetic flocculation clean water tank is communicated with the magnetic separation and recovery machine through a main pipeline; the reactor I, the reactor II and the reactor III are respectively connected with a PAC pipe, a magnetic powder pipe and a magnetic flocculation PAM pipe; and a water outlet pipe is arranged at the upper part of the side wall of the magnetic flocculation clean water tank.
And furthermore, stirrers are arranged on the reactor I, the reactor II, the reactor III and the flocculation sedimentation tank.
And an oil skimming machine is arranged at the bottom of the demulsification regulating reservoir.
Furthermore, liquid pumps are arranged on main pipelines among the demulsification adjusting tank, the flocculation sedimentation tank and the magnetic flocculation device; liquid pumps are arranged on main pipelines among the magnetic separation reclaimer, the ultrafiltration device, the pH adjusting tank, the cooling tower and the contact biochemical tank; a liquid pump is arranged on a main pipeline between the MBR reactor and the clean water tank; and liquid pumps are arranged on the supernatant return pipe and the filter pressing return pipe.
Furthermore, a sludge pump is arranged on a main pipeline between the magnetic flocculation clean water tank and the magnetic separation and recovery machine; and sludge pumps are arranged on the pipelines of the flocculation sedimentation tank, the sludge concentration tank and the plate-and-frame filter press, sludge pumps are arranged on the pipelines of the sludge recovery pipes, and sludge pumps are arranged on the biochemical sludge pipes.
The invention also provides a process for treating and recycling the silicon steel oily and emulsion wastewater by using the system, which comprises the following steps:
1) pretreatment of oil-containing and emulsion wastewater:
pumping the waste water containing oil and emulsion (hereinafter referred to as waste water) discharged by each production unit of silicon steel into a demulsification regulating reservoir, simultaneously, low-pressure waste heat steam (less than or equal to 2Mpa) of a steel mill heats the waste water to 60-70 ℃ through a waste heat steam pipe, and waste acid (hydrochloric acid, sulfuric acid and nitric acid) of a steel mill is used as a demulsifier and is thrown into a demulsification regulating reservoir through a demulsifier pipe, the pH value is regulated to 3-5, the hydraulic retention time is 3-4 h, the oil slick in the demulsification regulating reservoir is collected and recovered by an oil removal recovery device (the oil slick on the surface of the reservoir is scraped to an overflow pipe by the oil removal recovery device and automatically flows into an oil collecting tank, and then the oil is conveyed to a waste oil storage tank by a pneumatic diaphragm pump;
2) flocculation and precipitation treatment:
and (3) conveying the wastewater subjected to oil removal in the regulating tank to a coagulation tank for pretreatment to remove part of oil and COD:
a. the wastewater treated by the demulsification regulating reservoir is sent to a flocculation sedimentation tank,
b. adding NaOH solution into the flocculation sedimentation tank through an alkali solution pipe to adjust the pH value of the wastewater to 6.0, and then adding Ca (OH)2Adjusting the pH value of the wastewater to 6.0-9.0,
c. adding polyaluminum chloride and polyacrylamide, uniformly mixing and stirring, and performing hydraulic retention for 2-4 h; forming flocculate to remove part of oil, COD, fluoride ions and phosphate radicals in the wastewater; the flocculate is sent to a coking coal yard for coal blending treatment after being filter-pressed by a plate-and-frame filter press;
it is to be noted that lime milk solution (Ca (OH) is added into the flocculation sedimentation tank2) The purpose is two:
① accelerate the settling of flocs in the wastewater;
② remove fluorinion and phosphate in the wastewater, and reduce the biological scale of the ultrafiltration and subsequent cooling tower, see the reaction formulas (1) and (2).
The main reactions are as follows:
2F-+Ca2+→CaF2↓ (1)
PO3 4-+Ca2+→Ca3(PO4)2↓ (2)
3) magnetic flocculation treatment:
and pumping the wastewater subjected to flocculation precipitation to three reactors of a magnetic flocculation treatment system to remove floating oil and mechanical impurities:
c. respectively putting PAC, magnetic powder and PAM into the reactor I, the reactor II and the reactor III;
d. the water flow automatically flows to each reactor in turn according to the inverted S shape, oil stains and nonmagnetic suspended matters are pre-magnetized by flocculating and adding magnetic powder, so that the oil stains and the nonmagnetic suspended matters are combined with magnetic substances, and iron oxides, oil stains and suspended matters in the wastewater are effectively removed by magnetic separation;
c. after the magnetic sludge is treated by the magnetic separation circulating system, the magnetic powder can be recycled; the non-magnetic suspended matter sludge is dehydrated and then recycled or transported outside for disposal;
4) and (3) ultrafiltration treatment: the wastewater after magnetic flocculation treatment automatically flows into a ceramic membrane ultrafiltration device, and the wastewater after magnetic flocculation treatment enters the ultrafiltration device to be subjected to secondary ultrafiltration treatment to remove oil and COD in the wastewater; the effluent of the first stage and the second stage ultrafiltration is sent to a pH adjusting water tank, and the concentrated water after the second stage ultrafiltration is sent to an adjusting tank for demulsification and oil removal again;
it should be noted that, in the following description,
the mounting membrane tube cylinder of the ultrafiltration membrane system is a stainless steel shell, a ceramic support body and a ceramic membrane tube, and the membrane tube support body is Al2O3The material of the membrane is zirconia, and the aperture of the membrane is 50 nm.
And a circulating groove coil pipe automatic heating device is arranged in the ultrafiltration circulating box, and the heating temperature is 65-80 ℃.
After concentrated oil-containing wastewater of the ultrafiltration system is concentrated to a set index (COD in a circulating tank is 40000-50000 mg/L), a concentrated emulsion in a circulating tank of the ultrafiltration system is conveyed to an adjusting tank by an ultrafiltration delivery pump to be demulsified and degreased again; or a demulsifying box is arranged near the ultrafiltration water tank to perform heating demulsification and implement oil-water separation.
In order to prevent the flux of the ultrafiltration device from dropping too fast, the gel layer in the membrane tube is thickened continuously, the flux is reduced continuously, and the ultrafiltration device needs to be cleaned regularly to recover the water outlet flux of the ultrafiltration device. The cleaning device of the ultrafiltration system comprises acid cleaning, alkali cleaning and rinsing with clear water. And (4) discharging the cleaning drainage to a concentrated alkali wastewater adjusting tank of a water station for demulsification.
The pH value of the effluent after ultrafiltration is about 7.0-9.0 ifThe effluent is less than 7.0 or more than 9.0, NaOH solution or HCl/H is added2SO4Adjusting the pH value of the solution to 7.0-8.5, and cooling the solution in a cooling tower.
The ultrafiltration membrane tube cleaning agent is prepared by cleaning with alkali, oxidant and acid or anionic surfactant, acid solution and alkali solution, such as 6g/LNaOH +3g/LNaClO solution and HCl/HNO with pH of 33Cleaning with a solution combination, or 2-5% of anionic surfactant and HCl/HNO with pH of 33And cleaning the inorganic ceramic membrane by using a washing solution and an alkaline washing solution with the pH value of 11 for 2-12 hours according to the condition of filtering differential pressure.
5) Biochemical treatment:
after the temperature of the ultrafiltered effluent is reduced to 30-35 ℃ through a cooling tower, the effluent is sequentially sent into a contact biochemical tank and an MBR reactor, COD and SS of the effluent are reduced through biochemical action and microfiltration, and the effluent enters a clean water tank and is reused in a user, namely a circulating cooling water system (because the temperature of the ultrafiltered effluent is higher, the temperature is not reduced, bacterial reproduction in the biochemical tank is inhibited, and the temperature of the ultrafiltered water must be reduced to 30-35 ℃ so as to carry out biochemical reaction).
It is noted that aerators are arranged in the biological contact oxidation tank and the MBR reactor tank, and compressed air of a pipe network is used as a standby air source.
A suspended disc type filler is arranged in the biochemical contact oxidation tank, so that the activated sludge in the wastewater is intercepted, and the higher sludge concentration in the tank is kept.
6) Sludge dewatering system
Conveying sludge in the flocculation sedimentation tank and sludge in contact with the biochemical tank to a sludge concentration tank, and adding a 10-15% lime milk solution into the concentration tank to improve the sludge sedimentation performance; and (4) conveying the concentrated sludge to a plate-and-frame filter press for dehydration treatment, and transporting the dehydrated sludge outwards.
Further, in the step 2), the mass fraction of the NaOH solution is 30%; ca (OH)2The mass fraction of the solution is 20 percent; the adding amount of the polyaluminium chloride is 0.25kg/m3(ii) a The mass fraction of polyacrylamide is 1.5 per mill, and the adding amount is 0.5g/m3
Still further, in the step 3), the PAC, magnetic powder and PAM medicaments are dosed0.1-0.25 kg/m35-10 g/m of magnetic powder3And 0.1 to 1g/m3(ii) a The stirring speed of the reactor I is 100-200 r/min, the stirring speed of the reactor II is 80-150 r/min, and the stirring speed of the reactor III is 40-60 r/min; the hydraulic retention time of each reactor is 1-2 min.
Still further, in the step 5), contacting the HRT: 30-40 h.
The MBR reactor adopts an immersion type, and the main parameters are as follows:
HRT: 6.0-8.0 h, biochemical pool MLSS: 8000 to 12000mg/l,
the membrane pore diameter: the thickness of the film is 0.1 mu m,
membrane flux: not more than 0.30m3/m2.day,
The material of the film element: PTFE, the pH application range is 1-14,
a support structure: 304 stainless steel, and is made of stainless steel,
normal operating pressure: -60 to-100 KPa,
cleaning the membrane tube: and (3) adopting NaOH, NaClO solution and hydrochloric acid or nitric acid solution with the pH value of 2-3, and cleaning for 2-12 h.
The invention has the beneficial effects that:
⑴ the invention solves the problems of difficult treatment and non-recycling of high concentration organic oily wastewater of silicon steel oily/emulsified liquid wastewater, realizes zero discharge of silicon steel oily wastewater and emulsified liquid wastewater, and saves investment and treatment cost of wastewater treatment facilities;
⑵ the invention reduces the hazardous waste varieties such as waste filter paper (paper bag), waste activated carbon and the like generated in the traditional silicon steel oily wastewater treatment process, simultaneously reduces the iron content in the wastewater and reduces the impact problem to the subsequent membrane device;
⑶ the process of the invention has small floor area, less investment and better environmental protection and economic benefits.
Drawings
FIG. 1 is a schematic structural view of a silicon steel oil and emulsion wastewater treatment and recycling system;
FIG. 2 is a schematic structural diagram of a magnetic flocculation device;
in the figure, a demulsification adjusting tank 1, an oil-containing wastewater pipe 1.1, a demulsifier pipe 1.2, a heating coil pipe 1.3, an oil removal recovery device 1.4, an oil skimmer 1.5, a flocculation sedimentation tank 2, a flocculant pipe 2.1, an alkali liquor pipe 2.2, a coagulant aid pipe 2.3, a magnetic flocculation device 3, a reactor 3.1, a partition plate 3.2, a magnetic flocculation clear water tank 3.3, a water outlet pipe 3.31, a PAC pipe 3.4, a magnetic powder pipe 3.5, a magnetic flocculation PAM pipe 3.6, a magnetic separation recovery machine 4, a sludge recovery pipe 4.1, an ultrafiltration device 5, a concentrated water return pipe 5.1, a pH adjusting tank 6, an acid liquor pipe 6.1, a cooling tower 7, a contact biochemical tank 8, a biochemical sludge pipe 8.1, an MBR 9, a clear water tank 10, a sludge concentration tank 11, an upper clear water 11.1, a sludge PAM pipe 11.2, a plate frame return pipe 12, a filter press 12.1, a return pipe 13, a sludge stirrer, a liquid pump 14, an MBR filter press.
Detailed Description
The present invention is described in further detail below with reference to specific examples so as to be understood by those skilled in the art.
Example 1
The silicon steel oil-containing and emulsion wastewater treatment and recycling system shown in fig. 1-2 comprises a demulsification regulating reservoir 1, wherein an oil-containing wastewater pipe 1.1 and a demulsifier pipe 1.2 are arranged on the side wall of the demulsification regulating reservoir 1, a heating coil 1.3 is wound on the outer wall of the demulsification regulating reservoir 1, and the heating coil 1.3 is connected with an external waste heat steam pipe 16; a deoiling recovery device 1.4 is arranged in the demulsification adjusting tank 1; an oil skimmer 1.5 is arranged at the bottom of the demulsification regulating reservoir 1;
the demulsification adjusting tank 1 sequentially comprises a flocculation sedimentation tank 2, a magnetic flocculation device 3, a magnetic separation recovery machine 4, an ultrafiltration device 5, a pH adjusting tank 6, a cooling tower 7, a contact biochemical tank 8, an MBR (membrane bioreactor) 9 and a clean water tank 10 through a main pipeline; the flocculation sedimentation tank 2 is respectively connected with a flocculant pipe 2.1, an alkali solution pipe 2.2 and a coagulant aid pipe 2.3; the flocculation sedimentation tank 2 is provided with a stirrer 13;
the magnetic flocculation device 3 comprises a reactor 3.1, and the reactor 3.1 is separated into a reactor I, a reactor II and a reactor III by two partition plates 3.2; the height of the partition plate 3.2 between the reactor I and the reactor II is lower than the wall body of the reactor 3.1; the bottom of a partition plate 3.2 between the reactor II and the reactor III is communicated, so that the reactor II is communicated with the reactor III; the wall body of the reactor III is provided with a through hole which is communicated with the magnetic flocculation clean water tank 3.3; the bottom of the magnetic flocculation clean water tank 3.3 is communicated with the magnetic separation and recovery machine 4 through a main pipeline; the reactor I, the reactor II and the reactor III are respectively connected with a PAC pipe 3.4, a magnetic powder pipe 3.5 and a magnetic flocculation PAM pipe 3.6; a water outlet pipe 3.31 is arranged at the upper part of the side wall of the magnetic flocculation clean water tank 3.3; the reactor I, the reactor II and the reactor III are all provided with a stirrer 13.
The bottom of the flocculation sedimentation tank 2 is sequentially connected with a sludge concentration tank 11 and a plate-and-frame filter press 12 through pipelines, a sludge PAM pipe 11.2 is arranged on the sludge concentration tank 11, and the sludge concentration tank 11 is connected with the flocculation sedimentation tank 2 through a supernatant return pipe 11.1; the magnetic separation reclaimer 4 is connected with the plate-and-frame filter press 12 through a sludge reclaiming pipe 4.1; the plate-and-frame filter press 12 is communicated with the flocculation sedimentation tank 2 through a filter press return pipe 12.1; the contact biochemical tank 8 is communicated with a sludge concentration tank 11 through a biochemical sludge pipe 8.1; the ultrafiltration device 5 is connected with the demulsification regulating reservoir 1 through a concentrated water return pipe 5.1; an acid liquid pipe 6.1 is connected to the pH adjusting tank 6.
Liquid pumps 14 are arranged on main pipelines among the demulsification adjusting tank 1, the flocculation sedimentation tank 2 and the magnetic flocculation device 3; liquid pumps 14 are arranged on main pipelines among the magnetic separation recycling machine 4, the ultrafiltration device 5, the pH adjusting tank 6, the cooling tower 7 and the contact biochemical tank 8; a liquid pump 14 is arranged on a main pipeline between the MBR 9 and the clean water tank 10; and the supernatant return pipe 11.1 and the filter pressing return pipe 12.1 are both provided with a liquid pump 14.
A sludge pump 15 is arranged on a main pipeline between the magnetic flocculation clean water tank 3.3 and the magnetic separation and recovery machine 4; sludge pumps 15 are arranged on the pipelines of the flocculation sedimentation tank 2, the sludge concentration tank 11 and the plate-and-frame filter press 12, sludge pumps 15 are arranged on the pipelines of the sludge recovery pipes 4.1, and sludge pumps 15 are arranged on the biochemical sludge pipes 8.1.
The system for treating and recycling the silicon steel oily and emulsified liquid wastewater is used for treating and recycling the silicon steel oily and emulsified liquid wastewater
Example 2
The process for treating and recycling the wastewater containing the oil and the emulsion in the silicon steel comprises the following steps:
1) pretreatment of silicon steel oil-containing and emulsion wastewater: oily and emulsion wastewater (hereinafter referred to as wastewater) discharged by each silicon steel production unit is pumped into a demulsification regulating reservoir, a steam heating pipeline is arranged in the regulating reservoir, a heat source is derived from low-pressure waste heat steam (less than or equal to 2Mpa) of a steel mill, and the oily wastewater is heated to about 60 ℃. The waste acid (hydrochloric acid, sulfuric acid and nitric acid) demulsifier of the steel rolling mill is added into an adjusting tank, the pH value is adjusted to about 4, the hydraulic retention time is 3 hours, and the floating oil in the adjusting tank is collected and recovered by a floating oil collecting device. The oil removing device scrapes the floating oil on the surface of the pool body to the overflow pipe, automatically flows into the oil collecting tank, and then conveys the oil to the waste oil storage tank by the pneumatic diaphragm pump. The sludge deposited at the bottom of the regulating tank is periodically cleaned and transported outside the tank. In order to prevent the waste emulsion lift pump from sucking out the sludge at the bottom of the tank, a unique float-type telescopic water pump suction box is added on the water pump suction pipe.
2) Flocculation and precipitation treatment:
and the wastewater after the oil removal of the regulating tank is conveyed to a coagulation tank by a lifting pump for pretreatment to remove part of oil and COD. Sending the wastewater after oil recovery pretreatment into a flocculation sedimentation tank for retreatment, and removing partial oil, COD, fluoride ions, phosphate radicals and the like in the wastewater by forming flocculate from the entering wastewater.
Firstly adding caustic soda liquid 30% NaOH solution agent to adjust the pH value to 6.0, then adding 20% Ca (OH)2Adjusting pH to about 7.0, adding flocculant polyaluminium chloride at a dosage of 0.25kg/m3The coagulant aid is polyacrylamide with the concentration of 1.5 per mill and the adding amount of 0.5g/m3Uniformly mixing and stirring the mixture, and keeping the mixture for 2 hours by using hydraulic power; and (3) carrying out filter pressing on the sludge/waste residue after the flocculation precipitation and then sending the sludge/waste residue to coking for treatment.
3) Magnetic flocculation processing system: and pumping the wastewater subjected to flocculation precipitation into three reactors of a magnetic flocculation treatment system to remove floating oil and mechanical impurities. The magnetic flocculation system is provided with three reactors, namely a reactor I, a reactor II and a reactor III, wherein PAC, magnetic powder and PAM are sequentially added into the three reactors, and the dosage of the agents is 0.1kg/m35g/m of magnetic powder3、0.1g/m3And the water flow automatically flows to each reactor in turn according to the inverted S shape. For oil stains and nonmagnetic suspended matters passing through the paperThe patent flocculation and the magnetic powder feeding are carried out premagnetization, so that the magnetic powder is combined with magnetic substances, and iron oxide, oil stain and suspended matters in the wastewater can be effectively removed through magnetic separation.
The three reactors are all provided with a stirrer, the stirring speed of the reactor I is 100r/min, the stirring speed of the reactor II is 80r/min, and the stirring speed of the reactor III is 40 r/min. The hydraulic retention time of each reactor was 1 min. After the magnetic sludge is treated by the magnetic separation circulating system, the magnetic powder can be recycled; and the non-magnetic suspended matter sludge is dehydrated and then recycled or transported for disposal.
4) An ultrafiltration system: and the wastewater after magnetic flocculation automatically flows to a circulating tank of a ceramic membrane ultrafiltration system, and the iron powder and the oil sludge of the silicon steel oily and emulsified liquid wastewater after magnetic flocculation treatment are removed, and then the silicon steel oily and emulsified liquid wastewater enters an ultrafiltration circulating box for ultrafiltration treatment to remove oil and COD in the wastewater.
The ultrafiltration circulating box is internally provided with an automatic heating device of a circulating groove coil, and the heating temperature is 65 ℃.
After the concentrated oil-containing wastewater of the ultrafiltration system is concentrated to the set index (COD: 40000mg/L), the concentrated emulsion in the circulation tank of the ultrafiltration system is sent to an adjusting tank by an ultrafiltration delivery pump for demulsification and oil removal again. The pH value of the effluent after ultrafiltration is about 7.0-9.0, and if the pH value of the effluent is lower than 7.0 or higher than 9.0, NaOH solution or HCl/H solution is added2SO4Adjusting the pH value of the solution to 7.0-8.5, and cooling the solution in a cooling tower. The cleaning of the ceramic membrane tube adopts: 6g/LNaOH +3g/LNaClO solution + HNO with pH of 33The solution combination is washed for 8 h.
5) A biochemical treatment system: because the temperature of the ultrafiltration effluent is higher, the ultrafiltration effluent is not subjected to temperature reduction treatment, the bacterial reproduction in the biochemical pond is inhibited, the ultrafiltration effluent is required to be cooled to 35 ℃, the ultrafiltration effluent is sequentially sent into the contact biochemical pond and the MBR, the COD and SS of the effluent are reduced through biochemical action and microfiltration, and the effluent enters the clean water tank and is recycled to the circulating cooling water system. Aerators are arranged in the biological contact oxidation tank and the MBR reactor tank, and compressed air of a pipe network is used as a standby air source. The biochemical contact oxidation pond is internally provided with a hanging disc type filler, and the biochemical contact pond is HRT: and (5) 30 h.
The MBR reactor is immersed. The main parameters are as follows:
HRT: 6.0 h. Biochemical pool MLSS: 8000-12000 mg/l
The membrane pore diameter: 0.1 μm
Membrane flux: not more than 0.30m3/m2.day
The material of the film element: PTFE, pH application range 1-14
A support structure: 304 stainless steel
Normal operating pressure: -60 to-100 KPa
Cleaning a membrane module: and cleaning by adopting a combination of 4g/LNaOH +2g/LNaClO cleaning + HCl solution with the pH value of 3 for 4 h.
6) And (3) delivering the treated effluent into a clean water tank, finally reusing the effluent for users, pumping sludge in the oil-containing coagulating sedimentation tank, oil-containing biochemical sludge and the like into a sludge concentration tank through a sludge pump, delivering the concentrated sludge to a plate-and-frame filter press for dehydration, and transporting the dehydrated sludge outside. The water quality of the wastewater treated by the steps 1) to 6) is shown in the following table 1.
TABLE 1 EXAMPLE 2 effluent quality
As can be seen from the above table, the treated effluent contains suspended matter and CODCrIndexes such as SS, oil and the like all meet the emission requirements of newly-built enterprises in the table II of the discharge Standard of Water pollution in iron and Steel industry (GB13456-2012), and simultaneously meet the water quality requirements of the reclaimed water Standard for circulating Cooling Water (HJ, T3923-2007).
Example 3
The process for treating and recycling the wastewater containing the oil and the emulsion in the silicon steel comprises the following steps:
1) pretreatment of silicon steel oil-containing and emulsion wastewater: oily and emulsion wastewater (hereinafter referred to as wastewater) discharged by each silicon steel production unit is pumped into a demulsification regulating reservoir, a steam heating pipeline is arranged in the regulating reservoir, a heat source is derived from low-pressure waste heat steam (less than or equal to 2Mpa) of a steel mill, and the oily wastewater is heated to about 60 ℃. The waste acid (hydrochloric acid, sulfuric acid and nitric acid) demulsifier of the steel rolling mill is added into an adjusting tank, the pH value is adjusted to about 4, the hydraulic retention time is 3 hours, and the floating oil in the adjusting tank is collected and recovered by a floating oil collecting device. The oil removing device scrapes the floating oil on the surface of the pool body to the overflow pipe, automatically flows into the oil collecting tank, and then conveys the oil to the waste oil storage tank by the pneumatic diaphragm pump. The sludge deposited at the bottom of the regulating tank is periodically cleaned and transported outside the tank. In order to prevent the waste emulsion lift pump from sucking out the sludge at the bottom of the tank, a unique float-type telescopic water pump suction box is added on the water pump suction pipe.
2) Flocculation and precipitation treatment: and the wastewater after the oil removal of the regulating tank is conveyed to a coagulation tank by a lifting pump for pretreatment to remove part of oil and COD. Sending the wastewater after oil recovery pretreatment into a flocculation sedimentation tank for retreatment, and removing partial oil, COD, fluoride ions, phosphate radicals and the like in the wastewater by forming flocculate from the entering wastewater.
Firstly adding caustic soda liquid 30% NaOH solution agent to adjust the pH value to 6.0, then adding 20% Ca (OH)2Adjusting pH to about 7.0, adding flocculant polyaluminium chloride at a dosage of 0.40kg/m3The coagulant aid is polyacrylamide with the concentration of 1.5 per mill and the adding amount of 1.0g/m3Uniformly mixing and stirring the mixture, and keeping the mixture for 3 hours by using hydraulic power; and (3) carrying out filter pressing on the sludge/waste residue after the flocculation precipitation and then sending the sludge/waste residue to coking for treatment.
3) Magnetic flocculation processing system: and pumping the wastewater subjected to flocculation precipitation into three reactors of a magnetic flocculation treatment system to remove floating oil and mechanical impurities. The magnetic flocculation system is provided with three reactors, namely a reactor I, a reactor II and a reactor III, wherein PAC, magnetic powder and PAM are sequentially added into the three reactors, and the dosage of the agents is 0.15kg/m3Magnetic powder of 7.5g/m3、0.5g/m3And the water flow automatically flows to each reactor in turn according to the inverted S shape. To greasy dirt and non-magnetism suspended solid through this patent flocculation, throw the magnetic powder and carry out the premagnetization, make it and magnetic substance combine together, also can effectively get rid of iron oxide, greasy dirt and suspended solid in the waste water through the magnetic separation.
It is noted that the three reactors are all provided with a stirrer, the stirring speed of the reactor I is 150r/min, the stirring speed of the reactor II is 120r/min, and the stirring speed of the reactor III is 50 r/min. The hydraulic residence time of each reactor was 1.5 min. After the magnetic sludge is treated by the magnetic separation circulating system, the magnetic powder can be recycled; and the non-magnetic suspended matter sludge is dehydrated and then recycled or transported for disposal.
4) An ultrafiltration system: and the wastewater after magnetic flocculation automatically flows to a circulating tank of a ceramic membrane ultrafiltration system, and the iron powder and the oil sludge of the silicon steel oily and emulsified liquid wastewater after magnetic flocculation treatment are removed, and then the silicon steel oily and emulsified liquid wastewater enters an ultrafiltration circulating box for ultrafiltration treatment to remove oil and COD in the wastewater.
An automatic heating device of a circulating groove coil is arranged in the ultrafiltration circulating box, and the heating temperature is 70 ℃.
After the concentrated oil-containing wastewater of the ultrafiltration system is concentrated to the set index (COD: 45000mg/L), the concentrated emulsion in the circulation tank of the ultrafiltration system is sent to an adjusting tank by an ultrafiltration delivery pump for demulsification and oil removal again. The pH value of the effluent after ultrafiltration is about 7.0-9.0, and if the pH value of the effluent is lower than 7.0 or higher than 9.0, NaOH solution or HCl/H solution is added2SO4Adjusting the pH value of the solution to 7.0-8.5, and cooling the solution in a cooling tower.
The cleaning of the ceramic membrane tube adopts: 5% anionic surfactant, HNO of pH 33Washing liquid and alkaline washing liquid with pH of 11 are used for cleaning the inorganic ceramic membrane, and the chemical cleaning time is 6 hours.
5) A biochemical treatment system: because the temperature of the ultrafiltration effluent is higher, the ultrafiltration effluent is not subjected to temperature reduction treatment, the bacterial reproduction in the biochemical pond is inhibited, the ultrafiltration effluent is required to be cooled to 35 ℃, the ultrafiltration effluent is sequentially sent into the contact biochemical pond and the MBR, the COD and SS of the effluent are reduced through biochemical action and microfiltration, and the effluent enters the clean water tank and is recycled to the circulating cooling water system. Aerators are arranged in the biological contact oxidation tank and the MBR reactor tank, and compressed air of a pipe network is used as a standby air source. The biochemical contact oxidation pond is internally provided with a hanging disc type filler, and the biochemical contact pond is HRT: and (5) 35 h.
The MBR reactor is immersed. The main parameters are as follows:
HRT: 7.0 h. Biochemical pool MLSS: 8000-12000 mg/l
The membrane pore diameter: 0.1 μm
Membrane flux: not more than 0.30m3/m2.day
The material of the film element: PTFE, pH application range 1-14
A support structure: 304 stainless steel
Normal operating pressure: -60 to-100 KPa
Cleaning a membrane module: and cleaning with 3g/LNaOH +2g/LNaClO and HCl solution with pH of 3 in combination for 8 h.
6) And (3) delivering the treated effluent into a clean water tank, finally reusing the effluent for users, pumping sludge in the oil-containing coagulating sedimentation tank, oil-containing biochemical sludge and the like into a sludge concentration tank through a sludge pump, delivering the concentrated sludge to a plate-and-frame filter press for dehydration, and transporting the dehydrated sludge outside. The water quality of the wastewater treated by the steps 1) to 6) is shown in the following table 2.
Table 2 example 3 effluent quality
As can be seen from the above table, the treated effluent contains suspended matter and CODCrIndexes such as SS, oil and the like all meet the emission requirements of newly-built enterprises in the table II of the discharge Standard of Water pollution in iron and Steel industry (GB13456-2012), and simultaneously meet the water quality requirements of the reclaimed water Standard for circulating Cooling Water (HJ, T3923-2007).
Example 4
The process for treating and recycling the wastewater containing the oil and the emulsion in the silicon steel comprises the following steps:
1) pretreatment of silicon steel oil-containing and emulsion wastewater: oily and emulsion wastewater (hereinafter referred to as wastewater) discharged by each silicon steel production unit is pumped into a demulsification regulating reservoir, a steam heating pipeline is arranged in the regulating reservoir, a heat source is derived from low-pressure waste heat steam (less than or equal to 2Mpa) of a steel mill, and the oily wastewater is heated to about 60 ℃. The waste acid (hydrochloric acid, sulfuric acid and nitric acid) demulsifier of the steel rolling mill is added into an adjusting tank, the pH value is adjusted to about 4, the hydraulic retention time is 4 hours, and the floating oil in the adjusting tank is collected and recovered by a floating oil collecting device. The oil removing device scrapes the floating oil on the surface of the pool body to the overflow pipe, automatically flows into the oil collecting tank, and then conveys the oil to the waste oil storage tank by the pneumatic diaphragm pump. The sludge deposited at the bottom of the regulating tank is periodically cleaned and transported outside the tank. In order to prevent the waste emulsion lift pump from sucking out the sludge at the bottom of the tank, a unique float-type telescopic water pump suction box is added on the water pump suction pipe.
2) Flocculation and precipitation treatment: and the wastewater after the oil removal of the regulating tank is conveyed to a coagulation tank by a lifting pump for pretreatment to remove part of oil and COD. Sending the wastewater after oil recovery pretreatment into a flocculation sedimentation tank for retreatment, and removing partial oil, COD, fluoride ions, phosphate radicals and the like in the wastewater by forming flocculate from the entering wastewater.
Firstly adding caustic soda liquid 30% NaOH solution agent to adjust the pH value to 6.0, then adding 20% Ca (OH)2Adjusting pH to about 7.0, adding flocculant polyaluminium chloride at a dosage of 0.50kg/m3The coagulant aid is polyacrylamide with the concentration of 2 per mill and the adding amount of 1.5g/m3Uniformly mixing and stirring the mixture, and keeping the mixture for 4 hours by using hydraulic power; and (3) carrying out filter pressing on the sludge/waste residue after the flocculation precipitation and then sending the sludge/waste residue to coking for treatment.
3) Magnetic flocculation processing system: and pumping the wastewater subjected to flocculation precipitation into three reactors of a magnetic flocculation treatment system to remove floating oil and mechanical impurities. The magnetic flocculation system is provided with three reactors, namely a reactor I, a reactor II and a reactor III, wherein PAC, magnetic powder and PAM are sequentially added into the three reactors, and the dosage of the agents is 0.25kg/m3Magnetic powder of 10g/m3、1.0g/m3And the water flow automatically flows to each reactor in turn according to the inverted S shape. To greasy dirt and non-magnetism suspended solid through this patent flocculation, throw the magnetic powder and carry out the premagnetization, make it and magnetic substance combine together, also can effectively get rid of iron oxide, greasy dirt and suspended solid in the waste water through the magnetic separation.
It is noted that the three reactors are all provided with a stirrer, the stirring speed of the reactor I is 200r/min, the stirring speed of the reactor II is 150r/min, and the stirring speed of the reactor III is 60 r/min. The hydraulic residence time of each reactor was 2 min. After the magnetic sludge is treated by the magnetic separation circulating system, the magnetic powder can be recycled; and the non-magnetic suspended matter sludge is dehydrated and then recycled or transported for disposal.
4) An ultrafiltration system: and the wastewater after magnetic flocculation automatically flows to a circulating tank of a ceramic membrane ultrafiltration system, and the iron powder and the oil sludge of the silicon steel oily and emulsified liquid wastewater after magnetic flocculation treatment are removed, and then the silicon steel oily and emulsified liquid wastewater enters an ultrafiltration circulating box for ultrafiltration treatment to remove oil and COD in the wastewater.
The ultrafiltration circulating box is internally provided with an automatic heating device of a circulating groove coil, and the heating temperature is 80 ℃.
After the concentrated oil-containing wastewater of the ultrafiltration system is concentrated to the set index (COD: 50000mg/L), the concentrated emulsion in the circulation tank of the ultrafiltration system is sent to an adjusting tank by an ultrafiltration delivery pump for demulsification and oil removal again. The pH value of the effluent after ultrafiltration is about 7.0-9.0, and if the pH value of the effluent is lower than 7.0 or higher than 9.0, NaOH solution or HCl/H solution is added2SO4Adjusting the pH value of the solution to 7.0-8.5, and cooling the solution in a cooling tower.
The cleaning of the ceramic membrane tube adopts: 3% anionic surfactant, HNO of pH 33Washing liquid and alkaline washing liquid with pH of 11 are used for cleaning the inorganic ceramic membrane, and the chemical cleaning time is 12 hours.
5) A biochemical treatment system: because the temperature of the ultrafiltration effluent is higher, the ultrafiltration effluent is not subjected to temperature reduction treatment, the bacterial reproduction in the biochemical pond is inhibited, the ultrafiltration effluent is required to be cooled to 35 ℃, the ultrafiltration effluent is sequentially sent into the contact biochemical pond and the MBR, the COD and SS of the effluent are reduced through biochemical action and microfiltration, and the effluent enters the clean water tank and is recycled to the circulating cooling water system. Aerators are arranged in the biological contact oxidation tank and the MBR reactor tank, and compressed air of a pipe network is used as a standby air source. The biochemical contact oxidation pond is internally provided with a hanging disc type filler, and the biochemical contact pond is HRT: and (4) 40 h.
The MBR reactor is immersed. The main parameters are as follows:
HRT: 8.0 h. Biochemical pool MLSS: 8000-12000 mg/l
The membrane pore diameter: 0.1 μm
Membrane flux: not more than 0.30m3/m2.day
The material of the film element: PTFE, pH application range 1-14
A support structure: 304 stainless steel
Normal operating pressure: -60 to-100 KPa
Cleaning a membrane module: and cleaning with 6g/LNaOH +2g/LNaClO and HCl solution with pH of 3 in combination for 12 h.
6) And (3) delivering the treated effluent into a clean water tank, finally reusing the effluent for users, pumping sludge in the oil-containing coagulating sedimentation tank, oil-containing biochemical sludge and the like into a sludge concentration tank through a sludge pump, delivering the concentrated sludge to a plate-and-frame filter press for dehydration, and transporting the dehydrated sludge outside. The water quality of the wastewater treated by the steps 1) to 6) is shown in Table 3 below.
TABLE 3 quality of effluent of example 5
As can be seen from the above table, the treated effluent contains suspended matter and CODCrIndexes such as SS, oil and the like all meet the emission requirements of newly-built enterprises in the table II of the discharge Standard of Water pollution in iron and Steel industry (GB13456-2012), and simultaneously meet the water quality requirements of the reclaimed water Standard for circulating Cooling Water (HJ, T3923-2007).
Other parts not described in detail are prior art. Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and other embodiments can be obtained without inventive step according to the embodiments, and the embodiments are within the scope of the present invention.

Claims (10)

1. The utility model provides a silicon steel oiliness and emulsion waste water treatment and recycling system which characterized in that: the oil-containing waste water heating device comprises a demulsification regulating reservoir (1), wherein an oil-containing waste water pipe (1.1) and a demulsifier pipe (1.2) are arranged on the side wall of the demulsification regulating reservoir (1), a heating coil (1.3) is wound on the outer wall of the demulsification regulating reservoir (1), and the heating coil (1.3) is connected with an external waste heat steam pipe; an oil removal recovery device (1.4) is arranged in the demulsification adjusting tank (1); the demulsification regulating tank (1) is sequentially provided with a flocculation sedimentation tank (2), a magnetic flocculation device (3), a magnetic separation and recovery machine (4), an ultrafiltration device (5), a pH regulating tank (6), a cooling tower (7), a contact biochemical tank (8), an MBR (membrane bioreactor) reactor (9) and a clean water tank (10) through a main pipeline; the flocculation sedimentation tank (2) is respectively connected with a flocculant pipe (2.1), an alkali liquor pipe (2.2) and a coagulant aid pipe (2.3);
the bottom of the flocculation sedimentation tank (2) is sequentially connected with a sludge concentration tank (11) and a plate-and-frame filter press (12) through pipelines, a sludge PAM pipe (11.2) is arranged on the sludge concentration tank (11), and the sludge concentration tank (11) is connected with the flocculation sedimentation tank (2) through a supernatant return pipe (11.1); the magnetic separation recycling machine (4) is connected with the plate-and-frame filter press (12) through a sludge recycling pipe (4.1); the plate-and-frame filter press (12) is communicated with the flocculation sedimentation tank (2) through a filter press return pipe (12.1); the contact biochemical tank (8) is communicated with the sludge concentration tank (11) through a biochemical sludge pipe (8.1); the ultrafiltration device (5) is connected with the demulsification regulating reservoir (1) through a concentrated water return pipe (5.1); an acid liquid pipe (6.1) is connected to the pH adjusting tank (6).
2. The silicon steel oiliness and emulsion waste water treatment and recycling system of claim 1, characterized in that: the magnetic flocculation device (3) comprises a reactor (3.1), and the reactor (3.1) is separated into a reactor I, a reactor II and a reactor III by two partition plates (3.2); the height of the partition plate (3.2) between the reactor I and the reactor II is lower than the wall body of the reactor (3.1); the bottom of a partition plate (3.2) between the reactor II and the reactor III is communicated, so that the reactor II is communicated with the reactor III; the wall body of the reactor III is provided with a through hole which is communicated with a magnetic flocculation clean water tank (3.3); the bottom of the magnetic flocculation clean water tank (3.3) is communicated with the magnetic separation and recovery machine (4) through a main pipeline; the reactor I, the reactor II and the reactor III are respectively connected with a PAC pipe (3.4), a magnetic powder pipe (3.5) and a magnetic flocculation PAM pipe (3.6); and a water outlet pipe (3.31) is arranged at the upper part of the side wall of the magnetic flocculation clean water tank (3.3).
3. The silicon steel oiliness and emulsion waste water treatment and recycling system of claim 2, characterized in that: and the reactor I, the reactor II, the reactor III and the flocculation sedimentation tank (2) are all provided with stirrers (13).
4. The silicon steel oiliness and emulsion waste water treatment and recycling system of claim 1, characterized in that: an oil skimming machine (1.5) is arranged at the bottom of the demulsification regulating reservoir (1).
5. The silicon steel oiliness and emulsion waste water treatment and recycling system of claim 1, characterized in that: liquid pumps (14) are arranged on main pipelines among the demulsification adjusting tank (1), the flocculation sedimentation tank (2) and the magnetic flocculation device (3); liquid pumps (14) are arranged on main pipelines among the magnetic separation recycling machine (4), the ultrafiltration device (5), the pH adjusting tank (6), the cooling tower (7) and the contact biochemical pool (8); a liquid pump (14) is arranged on a main pipeline between the MBR (9) and the clean water tank (10); and liquid pumps (14) are arranged on the supernatant return pipe (11.1) and the filter pressing return pipe (12.1).
6. The silicon steel oiliness and emulsion waste water treatment and recycling system of claim 1, characterized in that: a sludge pump (15) is arranged on a main pipeline between the magnetic flocculation clean water tank (3.3) and the magnetic separation and recovery machine (4); sludge pumps (15) are arranged on pipelines of the flocculation sedimentation tank (2), the sludge concentration tank (11) and the plate-and-frame filter press (12), sludge pumps (15) are arranged on pipelines of the sludge recovery pipes (4.1), and sludge pumps (15) are arranged on the biochemical sludge pipes (8.1).
7. The process for treating and recycling wastewater containing oil and emulsion in silicon steel by using the system of claim 1, which is characterized by comprising the following steps of: the method comprises the following steps:
1) pretreatment of oil-containing and emulsion wastewater:
pumping oil-containing and emulsion wastewater discharged by each silicon steel production unit into a demulsification regulating reservoir, simultaneously heating the wastewater to 60-70 ℃ by using low-pressure waste heat steam of a steel mill through a waste heat steam pipe, using waste acid of a steel mill as a demulsifier to be thrown into the demulsification regulating reservoir 1 through a demulsifier pipe, regulating the pH value to 3-5, and allowing hydraulic retention time to be 3-4 h, and collecting and recovering floating oil in the demulsification regulating reservoir 1 through an oil removal recovery device;
2) flocculation and precipitation treatment:
and (3) conveying the wastewater subjected to oil removal in the regulating tank to a coagulation tank for pretreatment to remove part of oil and COD:
a. the wastewater treated by the demulsification regulating reservoir is sent to a flocculation sedimentation tank,
b. adding NaOH solution into the flocculation sedimentation tank through an alkali solution pipe to adjust the pH value of the wastewater to 6.0, and then adding Ca (OH)2Adjusting the pH value of the wastewater to 6.0-9.0,
c. adding polyaluminum chloride and polyacrylamide, uniformly mixing and stirring, and performing hydraulic retention for 2-4 h; forming flocculate to remove part of oil, COD, fluoride ions and phosphate radicals in the wastewater; the flocculate is sent to a coking coal yard for coal blending treatment after being filter-pressed by a plate-and-frame filter press;
3) magnetic flocculation treatment:
and pumping the wastewater subjected to flocculation precipitation to three reactors of a magnetic flocculation treatment system to remove floating oil and mechanical impurities:
a. respectively putting PAC, magnetic powder and PAM into the reactor I, the reactor II and the reactor III;
b. the water flow automatically flows to each reactor in turn according to the inverted S shape, oil stains and nonmagnetic suspended matters are pre-magnetized by flocculating and adding magnetic powder, so that the oil stains and the nonmagnetic suspended matters are combined with magnetic substances, and iron oxides, oil stains and suspended matters in the wastewater are effectively removed by magnetic separation;
c. after the magnetic sludge is treated by the magnetic separation circulating system, the magnetic powder can be recycled; the non-magnetic suspended matter sludge is dehydrated and then recycled or transported outside for disposal;
4) and (3) ultrafiltration treatment: the wastewater after magnetic flocculation treatment automatically flows into a ceramic membrane ultrafiltration device, and the wastewater after magnetic flocculation treatment enters the ultrafiltration device to be subjected to secondary ultrafiltration treatment to remove oil and COD in the wastewater; the effluent of the first stage and the second stage ultrafiltration is sent to a pH adjusting water tank, and the concentrated water after the second stage ultrafiltration is sent to an adjusting tank for demulsification and oil removal again;
5) biochemical treatment:
after the temperature of the ultrafiltered effluent is reduced to 30-35 ℃ by a cooling tower, the effluent is sequentially sent into a contact biochemical tank and an MBR (membrane bioreactor), COD (chemical oxygen demand) and SS (suspended solids) of the effluent are reduced by biochemical action and microfiltration, and the effluent enters a clean water tank and is reused for users, namely a circulating cooling water system;
6) sludge dewatering system
Conveying sludge in the flocculation sedimentation tank and sludge in contact with the biochemical tank to a sludge concentration tank, and adding a 10-15% lime milk solution into the concentration tank to improve the sludge sedimentation performance; and (4) conveying the concentrated sludge to a plate-and-frame filter press for dehydration treatment, and transporting the dehydrated sludge outwards.
8. The process according to claim 7, characterized in that: in the step 2), the mass fraction of the NaOH solution is 30%; ca (OH)2The mass fraction of the solution is 20 percent; the adding amount of the polyaluminium chloride is 0.25kg/m3(ii) a The mass fraction of polyacrylamide is 1.5 per mill, and the adding amount is 0.5g/m3
9. The process according to claim 7, characterized in that: in the step 3), the dosage of PAC, magnetic powder and PAM is 0.1-0.25 kg/m respectively35-10 g/m of magnetic powder3And 0.1 to 1g/m3(ii) a The stirring speed of the reactor I is 100-200 r/min, the stirring speed of the reactor II is 80-150 r/min, and the stirring speed of the reactor III is 40-60 r/min; the hydraulic retention time of each reactor is 1-2 min.
10. The process according to claim 7, characterized in that: in the step 5), contacting the HRT in a biochemical pool: 30-40 h;
the MBR reactor adopts an immersion type, and the main parameters are as follows:
HRT: 6.0-8.0 h, biochemical pool MLSS: 8000 to 12000mg/l,
the membrane pore diameter: the thickness of the film is 0.1 mu m,
membrane flux: not more than 0.30m3/m2.day,
The material of the film element: PTFE, the pH application range is 1-14,
a support structure: 304 stainless steel, and is made of stainless steel,
normal operating pressure: -60 to-100 KPa,
cleaning the membrane tube: and (3) adopting NaOH, NaClO solution and hydrochloric acid or nitric acid solution with the pH value of 2-3, and cleaning for 2-12 h.
CN201911355911.5A 2019-12-25 2019-12-25 Silicon steel oil-containing and emulsion wastewater treatment and recycling system and process thereof Pending CN110981107A (en)

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CN112939334A (en) * 2021-01-26 2021-06-11 山东泰山轧钢有限公司 Recycling and treating method for cold-rolling wastewater containing acid, alkali and thick oil

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