Home > Hongtek News >
Dec 03, 2011
Membrane Technology In Water Treatment Field
Membrane technology is a new interdisciplinary and practical technology, membrane separation process is a non-phase change, low-power physical separation process, with high efficiency, energy saving, pollution-free, easy to operate and versatile application. Half a century, the field of membrane technology has been in many widely used, is recognized as the most promising contemporary high-tech one.
The membrane separation products are manufactured using a special block of porous materials ability to physically remove the water retention of the way certain particle size of impurities. In the pressure-driven, small size of the material can be porous fiber walls to reach the other side of the membrane, while the larger size of the material can not be retained through the fiber wall, so as to achieve a large group of different screening solution sub-purposes.
Its accuracy and membrane filter pore size on its own. Usually used to the larger pore size as microfiltration,such as membrane pleated filter cartridges are the mainly used for micron filtration systems, it can be made of PP,PES,NYLON,PVDF,PTFE materials.
Membrane technology have important applications in water treatment field:
1,Drinking water treatment
Removal of the membrane generally includes daphnia, algae, protozoa, bacteria and even viruses, including microorganisms, combined with the second-generation processing technology can give full play to the advantages of the process, pathogenic microorganisms in water, turbidity, natural organic matter, micro-organic pollutants, ammonia and others have a better treatment effect, to meet people's increasing demands on water quality.
2,Wastewater treatment
According to the characteristics of filtration membranes, both in domestic sewage or industrial wastewater have been widely used. This is because it has the following
advantages:
- High efficiency for the impurity removal , quality of water is much better than traditional methods;
- Eliminate or significantly reduce the use of chemicals to avoid secondary pollution;
- The system is easy to automate,high reliability and simple operation.
- Industrial wastewater is not due to general technical standards, the use of membrane filtration technology can adequately used in treat wastewater.Effective use and save cost.
1).Daily sewage treatment
Municipal wastewater treatment plant effluent, can be used membrane bioreactor (MBR) technology for treatment, the treated water quality is better, can be used for water reuse, and the reactor, small footprint, low investment in equipment. Can be widely used in residential water reuse.
2).Oily waste water treatment
Oily wastewater there in three states: oil slicks, dispersed oil, emulsified oil. The first two easier to handle, can be mechanically separated, condensed sedimentation, activated carbon adsorption technology processing, the oil down to very low. However, emulsified oil containing surfactant and play a similar role of organic matter, oil to micron-sized ions in the water, gravity separation and coarse-grained method is more difficult. Filtration membranes to achieve their goals, it makes the water and low molecular weight organic compounds through the membrane, in order to achieve oil-water separation.For example, fuel oil for the oily wastewater is usually 100 ~ 1000 mg / L, exceeding the national discharge standard (<10 mg / L), it must be carried out degreasing treatment prior to discharge hollow fiber ultrafiltration technology applied in the operating pressure of 0.1MPa , water temperature 40 ℃, the membrane permeable speeds of up to 60 ~ 120 L / (m 2 · h), can be crude oil 200 ~ 1000 mg / L of wastewater treated to meet environmental emission standards.
3).Food industry wastewater treatment
Milk in the food industry, beverages, starch, yeast, tofu, meat processing in the course of wastewater contains large amounts of protein, starch, yeast, lactose and fat, which have some recovery value, and such wastewater a relatively high BOD and COD, pollute the environment. More difficult to deal with the general biochemical, and can not recover the useful materials can be achieved using membrane technology to purify waste water recycling and purpose.
4).Electroplating wastewater
Electroplating wastewater of high water, in which the cyanide, hexavalent chromium, nickel, copper, zinc, cadmium and other heavy metal ions are highly toxic to humans, animals and crops, etc. can cause serious harm. Electroplating wastewater biodegradability is characterized by small, and the inside of the metal ions is difficult to be absorbed by microorganisms. Electroplating wastewater treatment at home and abroad to use technology, the use of iron oxidation treatment of electroplating wastewater, although convenient and inexpensive raw materials, but a poor sense of color, sludge volume. Treatment of electroplating waste water using electrolysis, although the treatment effect is better, but the investment is large, more power, handling costs stay high.
5).Papermaking wastewater treatment
Paper Recovery in wastewater treatment is the most widely used chemical recovery combustion method, this method not only economic, there is no recovery of useful substances. Membrane used in papermaking wastewater, mainly concentrated on certain composition and recovery, and returned again through the water used in the process, mainly sulfonated lignin material is recycled, it can return the pulp to be in use, so we can create larger environmental and economic benefits.
3.Desalination
After half a century the development of desalination technology, technically, is relatively mature, large-scale sea water into fresh water around the world have emerged. Currently the major desalination methods are reverse osmosis (SWRO), multi-stage flash (MSF), multi-effect evaporation (MED) and pressure steam distillation (VC), etc., but for large desalination method only SWRO, MSF and MED. Although 70% of the capacity of the existing desalination is distillation, mainly multi-stage flash, but this situation is changing in recent years, reverse osmosis, low investment cost and low power consumption of its rapidly expanding market.
From the 1860s film technology has been used to solve the problem of water shortage in these countries, but many of reverse osmosis membrane desalination system faces serious pollution problems, mainly because the traditional reverse osmosis pretreatment system can not provide a reliable water into the . Therefore, the vast majority of desalination plants, well below its design work under water, leading to high cost of water. Membrane desalination projects at home and abroad more than the actual operation that filtration system can effectively control water quality, to provide high-quality reverse osmosis system into the water.
All in all ,we need to strengthen research and development capabilities, to promote the development of membrane technology industry, relying on scientific and technological progress, improving product quality, reduce costs, increase product variety, greater use of surface application of membrane technology to improve process design, system integration capabilities, the level of membrane preparation and membrane expand the variety of film and related mechanical and electrical products