The application of uf in water treatment

Ultrafiltration is a between microfiltration and nanofiltration membrane system, the average pore size in the 3 - 100 nm, ultrafiltration membrane is a kind of can solution purification, separation and enrichment of membrane separation technology and its entrapment mechanism mainly sieving effect, but sometimes the film hole is bigger than the solvent molecules, and is larger than the solute molecules, stock film and surface chemical characteristics also have the effect of entrapment, with the pressure difference on both sides of the membrane as the driving force, with ultrafiltration membrane as the filter medium, under certain pressure, when the water flow through the membrane surface, allow only water and solute in low molecular weight through, so as to achieve solution purification, separation, and the purpose of enrichment.
1, the application of ultrafiltration in water
1, water treatment,
ultrafiltration can go out to the water generally include water fleas, algae, protozoa, bacteria or even viruses, microorganisms, and the second generation process can give full play to the advantages of every process, to the pathogenic microorganisms in the water, turbidity, natural organic compounds, trace organic pollutants (pops), ammonia nitrogen, etc have good out effect, so as to meet the requirement for water quality is getting higher and higher.

2, waste water treatment according to the various characteristics of ultra-filtration membrane in sewage and is widely used in industrial waste water, sewage water treated with ultrafiltration is better to reuse, and due to general technical standard in industrial waste water, wastewater treatment using ultrafiltration technology can be fully.
1) Sewage treatment
urban sewage treatment plant, wastewater ultrafiltration membrane technology can be used for processing, the treated water quality is good, can be used for water reuse, and the reactor cover an area of an area small, low equipment investment, can be widely used in water reuse.
2) Oily wastewater treatment
the state of oily wastewater in three kinds: floating oil, dispersed oil, emulsified oil, two are easier to deal with money, can use mechanical separation, flocculation precipitation, activated carbon adsorption and so on processing make very low points, but the role of emulsified oil contains the surfactant and the same organic matter, oil content exist in micron scale the size of the ions in the water, the force of gravity separation and coarse graining method is more difficult, ultrafiltration membrane can achieve the purpose, he made the water and low molecule organic matter through the membrane, so as to realize the oil-water separation, such as oil field oil content in waste water is usually oil content is 100 - 1000 mg/l, the discharge of oil removal process must be conducted before application of hollow fiber ultrafiltration membrane technology, make the waste water after treatment reached 100 mg/l.
3)
food industry wastewater treatment in food industry, milk beverage, starch, yeast, tofu, meat processing, such as, formed in the process of wastewater containing large amounts of protein, starch, yeast, lactose and fat, etc. , all have certain collection value, and this kind of wastewater of BOD, COD, having high can cause pollution to the environment, the more difficult with the general biochemical method, and the recovery of useful substances, just using ultrafiltration method can be implemented using can achieve the purpose of purifying again.
4) Electroplating wastewater treatment
electroplating wastewater of high water consumption, the cyanide, hexavalent chromium, nickel, copper, zinc, iron, heavy metal ions, such as insulation strong toxicity, for people, animals and crops will cause serious impact. The characteristics of electroplating wastewater is biological sex, and the inside of the metal ions are difficult to be absorbed. Using ultrafiltration and reverse osmosis membrane application in the nickel plating waste water conductivity, nickel, nitrate and total organic carbon went out to tour in 97%, 99. 8%, 95% and 87%, through the ultrafiltration membrane as pretreatment, reverse osmosis membrane pollution decreased significantly, and reverse osmosis membrane flux can improve 30 - 50%.
5) Papermaking wastewater treatment
ultrafiltration application in papermaking wastewater, mainly for some components for enrichment and recovery, and through the water used in the return process, sulfonated lignin is the main recycling material, he can return to the pulp in the recycled again, so you can create more environmental benefits and economic benefits.
6)
small desalination desalination plant research is very clear, ultrafiltration system can effectively control the water of the sea water quality, provides the high quality for the reverse osmosis system of water, long-term test showed that the ultrafiltration system of water SDI values can be very good racing under 2, these tests before ultrafiltration systems don't have to be as any preprocessing, and application of seawater quality.
the role of ultrafiltration special bactericide in system
as a result of the material separation function of the ultrafiltration system depend on film, so he and other membrane separation equipment, in use process, will happen membrane pollution and flux decline, and one of the main reasons of membrane fouling is biological pollution, membrane flux decline caused by irreversible pollution, its severe enough to make the process difficult, causing the desalination efficiency of the device is reduced, shorten the service life and so on a series of adverse consequences.
system maintenance and prevention and control of
at present the most commonly used method to solve this problem is water and dedicated to the ultrafiltration system fungicides, the best sterilization frequency should be according to the actual situation of each system, there are two kinds of sterilization method to choose the intermittent and continuous dosing.
in the ultrafiltration system operation, should concentrate on the study of ultrafiltration membrane pollution control, and to nip in the bud, thus the system of economy, environmental protection and operation management to optimize and improve.