membrane technology
Microfiltration, nanofiltration, ultrafiltration and reverse osmosis are commonly used methods in membrane separation. Because membrane technology can separate macromolecules from small molecules without introducing other impurities in the treatment process, it is often used to recover various macromolecular raw materials, such as recovering polyvinyl alcohol slurry from printing and dyeing wastewater by ultrafiltration technology. At present, the main difficulties that limit the application and popularization of membrane technology in engineering are high cost, short life, easy pollution and scaling. With the development of membrane production technology, membrane technology will be more and more used in wastewater treatment.
Magnetic separation technology
Magnetic separation technology is a new water treatment technology developed in recent years, which uses the magnetism of impurity particles in wastewater to separate. For nonmagnetic or weakly magnetic particles in water, magnetic inoculation technology can make them magnetic. There are three methods to apply magnetic separation technology to wastewater treatment: direct magnetic separation, indirect magnetic separation and microbial-magnetic separation. At present, the research of magnetization technology mainly includes magnetic agglomeration technology, iron salt precipitation technology, iron powder method, ferrite method and so on. Representative magnetic separation equipment are disc magnetic separators and high gradient magnetic filters. At present, magnetic separation technology is still in the laboratory research stage, so it can not be applied to practical engineering practice.
Fenton and Fenton-like oxidation
The typical Fenton reagent is composed of Fe2? Oh, which leads to the oxidative degradation of organic matter. Because Fenton process takes a long time to treat wastewater, and a large number of reagents are used, excessive Fe2 will increase the COD in the treated wastewater, resulting in secondary pollution. In recent years, ultraviolet light and visible light have been introduced into Fenton system, and other transition metals have been studied to replace Fe2. These methods can significantly enhance the oxidative degradation ability of Fenton reagent, reduce the dosage of Fenton reagent and reduce the treatment cost, which are collectively called Fenton-like reactions. Fenton method has mild reaction conditions, simple equipment and wide application range; It can not only be used as a multi-band treatment technology, but also be combined with other methods such as coagulation and sedimentation, activated carbon and biological treatment, and can be used as a pretreatment or advanced treatment method for refractory organic wastewater.
Electrochemical (catalytic) oxidation
Electrochemical (catalytic) oxidation technology directly degrades organic matter through anode reaction, or generates hydroxyl radical through anode reaction. OH), ozone and other oxidants degrade organic matter. Electrochemical oxidation includes one-dimensional, two-dimensional and three-dimensional electrode systems. Because of the micro-electric field electrolysis of three-dimensional electrode system, it is highly respected at present. Three-dimensional electrode is a traditional two-dimensional electrolytic cell, which is filled with granular or other crumb-like working electrode materials. The surface of the filling material is charged and becomes the roof of the world, and the surface of the working electrode material undergoes electrochemical reaction. Compared with the two-dimensional plate electrode, the three-dimensional electrode has a large specific surface area, which can increase the surface-to-body ratio of the electrolytic cell, provide a large current intensity at a low current density, have a small particle spacing, a fast mass transfer speed and a high time-space conversion efficiency, so that the current efficiency is high and the treatment effect is good. The three-dimensional electrode can be used to treat domestic sewage and refractory organic wastewater such as pesticides, dyes, pharmaceuticals, phenol-containing wastewater, metal ions, landfill leachate, etc.
Iron-carbon micro-electrolysis treatment technology
Iron-carbon micro-electrolysis is a good process to treat wastewater by using the reaction principle of iron-carbon primary battery, which is also called internal electrolysis and iron filings filtration. Iron-carbon micro-electrolysis is a comprehensive function of electrochemical redox, electrochemical enrichment of flocs, coagulation of electrochemical reaction products, adsorption of new flocs and bed filtration, among which redox, electrocoagulation and coagulation are the main functions. When iron filings are immersed in wastewater containing a lot of electrolytes, countless tiny primary cells will be formed. After coke is added to the iron filings, the iron filings contact with coke particles, further forming a large primary battery, so that the iron filings are corroded not only by tiny primary batteries, but also by large primary batteries, thus accelerating the electrochemical reaction. The method has the advantages of wide application range, good treatment effect, long service life, low cost and convenient operation and maintenance. It uses scrap iron as raw material, does not consume power resources, and has the significance of "treating waste with waste". At present, iron-carbon micro-electrolysis filler has been widely used in printing and dyeing, pesticide/pharmaceutical, heavy metal, petrochemical and petroleum wastewater and landfill leachate treatment, and achieved good results. The treatment effect of TPFC iron-carbon filler developed and produced by our company on various wastewater, you can see the treatment effect of TPFC iron-carbon micro-electrolysis filler on various wastewater.
Ozone oxidation
Ozone is a strong oxidant, which reacts quickly with reducing pollutants, is convenient to use, does not produce secondary pollution, and can be used for disinfection, decoloration, deodorization, removal of organic matter and reduction of COD of sewage. The ozone oxidation method used in multi-zone has high cost and high treatment cost, and its oxidation reaction is selective, which has poor oxidation effect on some halogenated hydrocarbons and pesticides. Therefore, in recent years, related combination technologies aimed at improving ozone oxidation efficiency have been developed, among which UV/O3, H2O2/O3, UV/H2O2/O3 and other combination methods can not only improve the oxidation rate and efficiency, but also oxidize organic substances that are difficult to oxidize and degrade when ozone is in multiple bands. Because of the low solubility of ozone in water, low efficiency of ozone generation and high energy consumption, increasing the solubility of ozone in water, improving the utilization rate of ozone and developing an ozone generator with high efficiency and low energy consumption have become the main research directions.
Wet (catalytic) oxidation
Wet (catalytic) oxidation is to (catalytically) oxidize dissolved or suspended organic matter or reduced inorganic matter in water at high temperature (150~350℃) and high pressure (0.5~20MPa) under the action of catalyst, so as to remove pollutants. Wet air (catalytic) oxidation can be used to treat industrial wastewater such as municipal sludge and acrylonitrile, coking, printing and dyeing, and pesticide wastewater containing phenol, chlorinated hydrocarbons, organophosphorus and organosulfur compounds.
Plasma water treatment technology
Low-temperature plasma water treatment technology, including high-voltage pulse discharge plasma water treatment technology and glow discharge plasma water treatment technology, can completely oxidize and decompose pollutants in water by directly generating plasma in aqueous solution by discharge or introducing active particles in gas discharge plasma into water. The direct pulse discharge in aqueous solution can be carried out at normal temperature and pressure. In the whole discharge process, in-situ chemical oxide species will be produced in the aqueous solution, which will oxidize and degrade the organic matter. This technology is economical and effective for the treatment of low concentration organic matter. In addition, the reactor form using pulsed discharge plasma water treatment technology can be flexibly adjusted, the operation process is simple, and the corresponding maintenance cost is also low. Due to the limitation of discharge equipment, the energy utilization rate of this process to degrade organic matter is low, and the application of plasma technology in water treatment is still in the research and development stage.
Ultrasonic oxidation
The organic pollutants in water are irradiated by ultrasonic with the frequency of 15~ 1000kHz, which is a physical and chemical process caused by cavitation effect. Ultrasonic wave can not only improve the reaction conditions, speed up the reaction and increase the reaction yield, but also make some difficult chemical reactions come true. It combines the characteristics of water treatment technologies such as advanced oxidation, incineration and supercritical oxidation. In addition, the operation is simple and the requirements for equipment are low. It is of great significance in sewage treatment, especially in degrading highly toxic and refractory organic pollutants in wastewater, accelerating the degradation speed of organic pollutants, realizing the harmlessness of industrial wastewater pollutants and avoiding the influence of secondary pollution. In recent years, there are more and more researches on direct or enhanced treatment of organic wastewater by ultrasound, involving degradation mechanism, kinetics, intermediate products, influencing factors, system optimization and so on.
Radiation technology
Since 1970s, with the development of large cobalt source and electron accelerator technology, the problem of radiation source in the application of radiation technology has been gradually improved. The research on the treatment of pollutants in wastewater by radiation technology has attracted the attention and attention of all countries. Compared with traditional chemical oxidation, using radiation technology to treat pollutants does not need to add or only needs to add a small amount of chemical reagents, and will not produce secondary pollution. Has the advantages of high degradation efficiency, fast reaction speed and complete degradation of pollutants. In addition, when ionizing radiation is combined with catalytic oxidation means such as oxygen and ozone, a "synergistic effect" will occur. Therefore, the radiation technology for treating pollutants is a clean and sustainable technology, which has been listed as the main research direction of peaceful use of atomic energy by the International Atomic Energy Agency in 2 1 century.
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