A kind of system of steel composite wastewater recycle-water double-membrane demineralization and technology
Technical field
The invention belongs to steel iron wastewater and handle and the reuse technology field, particularly a kind of system of steel composite wastewater recycle-water double-membrane demineralization and technology are applicable to the advanced treatment and the desalination reuse of iron and steel composite wastewater.
Background technology
Reusing sewage is that iron and steel enterprise realizes an important channel of " water-saving and emission-reducing ".Be water saving, improve the repeating utilization factor of whole Steel Plant water resources, drop into sewage work in succession as water rich and influential family's Iron And Steel Company, the water after will handling through sewage work carry out reuse, to save the magnitude of recruitment of source water; Simultaneously, because factors such as whole Steel Plant water system concentrates, evaporation, enter the sewage quality complexity of sewage work, saltiness is higher, the reusing sewage that does not have advanced desalination to handle, the corrosion tendency that cause the saltiness of Steel Plant's water system to raise, cycles of concentration improves difficult and aggravation system etc.
At present, domestic Iron And Steel Company be mostly to composite wastewater (containing the factory effluent that is no more than 30% sanitary sewage) adopt lime softening-clarification-filtration-sterilization process carries out pair embrane method desalination reuses after reaching the reuse water requirement.Because sewage work's quality of reused water is complicated and fluctuation is bigger, two embrane method desalting system life-spans are very short, and operation is very unstable.So, some company has increased some pre-treatment measures before two embrane method desalting systems, as increase the cooling tower cooling in summer, increase little flocculation and remove part suspended substance, colloid and COD, increase laminated filter and remove the part suspended substance, the injection Powdered Activated Carbon is removed and is partly dissolved organic matter before raw water box, or even the combination of these measures.Obviously, these measures all can only improve the water quality that enters two embrane method desalting systems from some aspect; Though some measure can solve some problems, but produced new problem, as adopting injection powder process of active carbon, though the content of economic reduction dissolved organic matter comparatively easily makes follow-up laminated filter and UF stop up.
Above-mentioned situation causes the two embrane method desalting systems of existing composite wastewater reuse water that following subject matter is arranged: it is dirty stifled that 1. ultrafiltration system is subject to colloid, causes transmembrane pressure to raise, and membrane flux reduces, and cleaning frequency obviously increases; 2. reverse osmosis system is subject to the heavy-metal pollution such as iron, manganese in the sewage, or at some dead angles owing to microorganism is grown in organic existence.3. stifled operating pressure rising, the increasing of medicine consumption, the power consumption of two embrane method desalting systems of all making of various dirts increases.In view of the above problems, should update the steel composite wastewater recycle-water double-membrane demineralization technology, its key problem is to strengthen two pretreated abilities of embrane method desalination.
Summary of the invention
The system and the technology that the objective of the invention is to overcome the deficiencies in the prior art and a kind of steel composite wastewater recycle-water double-membrane demineralization is provided realize sewage recycling and Steel Plant's sewage " zero release ".
System of the present invention comprises cooling tower 1, raw water box 2, raw water pump 3, micro flocculating filter device 4, by-pass flow water pump 5, by-pass flow activated carbon filtration jar 6, water pump 7, laminated filter 8, ultrafiltration system 9, accurate filter 10, reverse osmosis system 11.Wherein, cooling tower 1, raw water box 2, raw water pump 3, micro flocculating filter device 4, by-pass flow water pump 5, by-pass flow activated carbon filtration jar 6, water pump 7, laminated filter 8 form two embrane method desalination pretreatment systems by pipe connection successively, and ultrafiltration system 9, accurate filter 10, reverse osmosis system 11, reverse osmosis desalination water tank 12 form two embrane method desalting systems by pipe connection successively.
Micro flocculating filter device of the present invention links to each other with laminated filter with water pump successively by pipeline, on the pipeline between micro flocculating filter device and the water pump, by-pass flow water pump and by-pass flow activated carbon filtration jar are set, and by-pass flow water pump and by-pass flow activated carbon filtration jar pass through pipe connection.
The filtering accuracy of laminated filter of the present invention is got 20~200 μ m; The filtering accuracy of described accurate filter is got 5~20 μ m.
Technology of the present invention is undertaken by following operation:
1. two embrane method desalination pre-treatment: the iron and steel composite wastewater is reached suspended substance after treatment less than 25mg/L, COD
CrLess than 40mg/L, mineral oil less than 3mg/L, temporary hardness less than the reuse water of 100mg/L successively after overcooling, preoxidation, micro flocculating filter, by-pass flow activated carbon filtration and laminated filter are handled, remove most of heavy metal ion, colloid, organism and mineral oil, make its suspended substance less than 5mg/L, COD
CrLess than 10mg/L, mineral oil less than 0.5mg/L, iron less than 0.5mg/L, manganese less than 0.5mg/L.
2. two embrane method desalinations: will handle through ultra-filtration equipment earlier through pretreated water, and reach the requirement of SDI≤3, and carry out the desalination processing through entering reverse osmosis unit behind the accurate filter again.
Preoxidation of the present invention is to utilize the water collecting basin of cooling tower or raw water box to carry out preoxidation, and preoxidation can be adopted the way of aeration or dosing oxidation, to promote the oxidation of iron, manganese.
The filtrate of micro flocculating filter device of the present invention adopts quartz sand or manganese sand, and (hydraulic detention time, english abbreviation are HRT to hydraulic detention time, and popular saying is exactly " duration of contact " or " action time ".) HRT=5~30min, design filtering velocity 8~20m/h.
The flocculation agent of micro flocculating filter device of the present invention is selected FeCl for use
3(iron trichloride), PFC (poly-ferric chloride) or PFS (bodied ferric sulfate), dosage is 2~15mg/L, or adds PAC (polymerize aluminum chloride), dosage is 1~15mg/L.
It is filtrate that by-pass flow activated carbon filtration jar of the present invention adopts granulated active carbon, adopts the fixed bed mode, and the by-pass flow water yield is 0.1~100% of a Total Water, and concrete ratio needs to set hydraulic detention time HRT=1~15min according to quality of reused water.
The present invention has the technological improvement of 2 innovations: the one, improve the removal ability of iron, manganese, and adopt and carry out preoxidation at the water collecting basin of cooling tower or raw water box and realize this effect; The 2nd, micro flocculating filter-activated carbon filtration combination process has the Synergistic degradation effect to turbidity, colloid, the organism of sewage, and adopts granulated active carbon to be difficult for stopping up follow up device, laminated filter is set can guarantees that more ultrafiltration system is not blocked.
Advantage of the present invention and positively effect are:
Filter combined mode iron and steel composite wastewater reuse water is handled with preoxidation, micro flocculating filter, by-pass flow activated carbon filtration, self-stip, under the situation that only needs to increase a small amount of investment and take up an area of, improved the stable and work-ing life of two embrane method desalting systems greatly, greatly reduce medicine consumption and power consumption, effectively realized sewage recycling and sewage " zero release ", the better economic effect has been arranged.
2. micro flocculating filter-activated carbon filtration combination process has the Synergistic degradation effect to turbidity, colloid, the organism of sewage, increases preoxidation and can further strengthen iron, manganese, organic Degradation before micro flocculating filter.The present invention has important practical to be worth to steel composite wastewater recycle-water double-membrane demineralization.
Description of drawings
Fig. 1 is a steel composite wastewater recycle-water double-membrane demineralization system diagram of the present invention.Wherein, cooling tower 1, raw water box 2, raw water pump 3, micro flocculating filter device 4, by-pass flow water pump 5, by-pass flow activated carbon filtration jar 6, water pump 7, laminated filter 8, ultrafiltration system 9, accurate filter 10, reverse osmosis system 11, reverse osmosis desalination water tank 12, preoxidation with pressurized air or oxidation medicament 13, little flocculation with flocculation agent 14, sterilant 15, transfer pH with hydrochloric acid 16, Scale inhibitors 17, reductive agent 18, accent pH with sodium hydroxide 19, iron and steel composite wastewater reuse water 20, de-mineralized water confess 21, the dense water 22 of ultrafiltration, reverse osmosis concentrated water 23.
Embodiment
The present invention will be further described below in conjunction with accompanying drawing.
The present invention is applicable to the advanced treatment and the desalination reuse of iron and steel composite wastewater.
1. two embrane method desalination pre-treatment: the iron and steel composite wastewater is reached suspended substance after treatment less than 25mg/L, COD
CrHandle through overcooling, preoxidation, micro flocculating filter, by-pass flow activated carbon filtration and laminated filter successively less than the reuse water of 100mg/L less than 3mg/L, temporary hardness less than 40mg/L, mineral oil.The present invention through Technological Economy relatively determines to adopt water collecting basin or raw water box at cooling tower to carry out aeration preoxidation, than adding medicament oxidation economy, and follow-up pair of embrane method desalting system not have to damage substantially.For by-pass flow activated carbon filtration jar; adopt granulated active carbon to be difficult for stopping up follow up device; laminated filter is set guarantees that more ultrafiltration system is not blocked; adopt the fixed bed mode; the by-pass flow water yield is 0.1~100% of a Total Water; concrete ratio can be regulated hydraulic detention time HRT=1~15min according to quality of reused water.
The composite wastewater reuse water can be removed most of heavy metal ion, colloid, organism and mineral oil through after the pre-treatment, makes its suspended substance less than 5mg/L, COD
CrLess than 10mg/L, mineral oil less than 0.5mg/L, iron less than 0.5mg/L, manganese less than 0.5mg/L.
2. two embrane method desalting systems: will handle through ultra-filtration equipment earlier through pretreated water, and remove colloid silicon, biological pollutant, particulate matter, turbidity, bacterium in the water, and reach the requirement of SDI≤3, and satisfy the requirement that enters reverse osmosis, and enter ultrafiltration and produce water tank.Pass through accurate filter again, the tapered structure of its filter opening, filtration can enter the depths, forms Depth Filtration, and pollutant holding capability is big, and the life-span is long, is convenient to quick replacing, and follow-up reverse osmosis unit is played good security personnel's effect.Enter reverse osmosis unit afterwards and carry out the desalination processing, the reverse osmosis unit major function is the salinity that removes in the water, and ratio of desalinization is greater than 96%.
Specific embodiment below is provided:
1. the pre-treatment of two embrane method desalination: the iron and steel composite wastewater that certain Iron And Steel Company mixes smelting, rolling effluent and all the other about sanitary sewages of about 24% through coarse rack-fine fack-lime softening-after high dense settling pond-pH regulator-V-type filter tank-add NaClO disinfects, produce into suspended substance less than 20mg/L, COD
CrLess than 30mg/L, mineral oil less than 3mg/L, temporary hardness reuse water less than 100mg/L, chlorine residue 0.5mg/L, more successively through the overcooling control water temperature at 8~30 ℃, the preoxidation of cooling tower water collecting basin aeration, former pond, raw water pump, to select quartz sand for use be filtrate and the FeCl that adds 3~10mg/L
3(iron trichloride) carries out 10~50% of micro flocculating filter, setting Total Water and carries out the by-pass flow activated carbon filtration, is the laminated filter processing of 55 μ m again through filtering accuracy.In addition, for suppressing bacterial reproduction in the water, behind raw water pump, need add sterilant and carry out germicidal treatment, sterilant can adopt NaClO (clorox), and adding dose is 0.5~3mg/L, in order to guarantee the sterilization effect of NaClO, also need regulate pH 5.5~7.0, can add a certain amount of hydrochloric acid.The composite wastewater reuse water can be removed most of heavy metal ion, colloid, organism and mineral oil through after the pre-treatment, guarantees that suspended substance is less than 5mg/L, COD
CrLess than 10mg/L, mineral oil less than 0.5mg/L, iron less than 0.1mg/L, manganese less than 0.05mg/L.
2. two embrane method desalting systems: will handle through the inner pressed ultra-filtration equipment earlier through pretreated water, and reach the requirement of SDI≤2, and send into ultrafiltration and produce water tank, the dense water of ultrafiltration then drains into network of drains.Be to enter reverse osmosis unit after boosting with high-pressure pump behind the accurate filter of 5 μ m to carry out desalination and handle through precision again.Water is produced in ultrafiltration need add reductive agent and Scale inhibitors and the mixing of process line mixer before entering accurate filter, wherein Scale inhibitors can be PTP0100 efficient scale/dispersion agent that the U.S. clear power company produces, and adding dosage is 3~5mg/L; Reductive agent adopts NaHSO
3(sodium bisulfite), dosing dosage are 1~3mg/L, guarantee to enter the preceding cl content of reverse osmosis unit less than 0.1mg/L.The concentrated water drainage of reverse osmosis is gone out stewing slag, the reverse osmosis permeate water adds NaOH (sodium hydroxide) and regulates about pH to 7.0, send sweet-water tank to through the line mixer mixing, use as the steel-making sheet billet continuous casting, also can be used as make up water or other water of productive use of circulating water system for the associated user.