Industrial wastewater treatment
Industrial wastewater refers to the wastewater, sewage and waste liquid produced in the industrial production process, which contains industrial production materials, intermediate products and products that are lost with the water, and pollutants generated during the production process. With the rapid development of industry, the types and quantities of wastewater have increased rapidly, and the pollution of water bodies has become increasingly extensive and serious, threatening human health and safety. Therefore, for the protection of the environment, the treatment of industrial wastewater is more important than the treatment of municipal wastewater. Among the many water treatment enterprises, the wastewater treatment equipment developed and produced by Henan Zhonglan Group adopts advanced technical operations and uses first-class wastewater treatment technology to solve many industrial wastewater treatment problems. The following briefly introduces the new technologies of today's industrial wastewater treatment.
Membrane separation methods commonly used are microfiltration, nanofiltration, ultrafiltration and reverse osmosis. Because membrane technology does not introduce other impurities during the process, it can achieve the separation of macromolecules and small molecules, so it is often used for the recovery of various macromolecular raw materials, such as the use of ultrafiltration technology to recover polyvinyl alcohol slurry of printing and dyeing wastewater. At present, the main difficulties in limiting the application and promotion of membrane technology engineering are the high cost of the membrane, the short life, the susceptibility to fouling and fouling. With the development of membrane production technology, membrane technology will be more and more applied in the field of wastewater treatment.
Magnetic separation technology
Magnetic separation technology is a new type of water treatment technology developed in recent years that uses the magnetic properties of impurity particles in wastewater for separation. For non-magnetic or weakly magnetic particles in water, magnetic inoculation technology can be used to make them magnetic. There are three methods of magnetic separation technology used in wastewater treatment: direct magnetic separation method, indirect magnetic separation method and microorganism-magnetic separation method. The currently researched magnetization technologies mainly include magnetic agglomeration technology, iron salt co-precipitation technology, iron powder method, ferrite method, etc. The representative magnetic separation devices are disc magnetic separators and high gradient magnetic filters. At present, magnetic separation technology is still in the laboratory research stage and cannot be applied to actual engineering practice.
Fenton and Fenton-like oxidation
The typical Fenton reagent is Fe2 catalyzed to decompose H2O2 to generate? OH, which triggers the oxidative degradation of organic matter. Because the Fenton process takes a long time to treat wastewater, a large amount of reagents are used, and excess Fe2 will increase the COD in the wastewater after treatment and cause secondary pollution. In recent years, people have introduced ultraviolet and visible light into the Fenton system and studied the use of other transition metals instead of Fe2. These methods can significantly enhance the oxidative degradation of organic substances by Fenton reagents, reduce the amount of Fenton reagents, and reduce processing costs. Fenton reaction. The Fenton method has mild reaction conditions, relatively simple equipment, and a wide range of applications. It can be used as a separate treatment technology or combined with other methods, such as coagulation sedimentation, activated carbon, and biological treatment. Pretreatment or advanced treatment method for degrading organic wastewater.
Electrochemical (catalytic) oxidation
Electrochemical (catalytic) oxidation technology directly degrades organics through anodic reactions, or generates oxidants such as hydroxyl radicals (? OH) and ozone through anodic reactions to degrade organics. Electrochemical (catalytic) oxidation includes one-, two-, and three-dimensional electrode systems. Due to the micro-field electrolysis of the three-dimensional electrode system, it is currently highly regarded. The three-dimensional electrode is a granular or other chip-shaped working electrode material filled between the electrodes of a traditional two-dimensional electrolytic cell, and the surface of the filled material is charged to become a third electrode, and an electrochemical reaction can occur on the surface of the working electrode material. Compared with two-dimensional flat electrodes, three-dimensional electrodes have a large specific surface, can increase the area ratio of the electrolytic cell, can provide a larger current intensity at a lower current density, have a smaller particle spacing and a high mass transfer rate, and space-time conversion. High efficiency, so high current efficiency and good processing effect. Three-dimensional electrodes can be used to treat domestic sewage, pesticides, dyes, pharmaceuticals, phenol-containing wastewater and other difficult-to-degrade organic wastewater, metal ions, landfill leachate, etc.
Iron-carbon micro-electrolytic treatment technology
The iron-carbon micro-electrolysis method is a good process for treating wastewater by using the principle of Fe / C galvanic cell reaction. It is also called internal electrolysis method and iron filing method. The iron-carbon micro-electrolysis method is a combination of the effects of electrochemical oxidation-reduction, electrochemical enrichment on flocs, and the aggregation of electrochemical reaction products, adsorption of new flocs, and bed filtration. It is redox and electric agglomeration and agglomeration. When iron filings are immersed in wastewater containing a large amount of electrolyte, countless tiny galvanic cells are formed. After coke is added to the iron filings, the iron filings contact the coke particles to further form a large primary battery, so that the iron filings are the basis of the corrosion of the microprimary battery. It is also corroded by Ohara cells, which accelerates the progress of the electrochemical reaction. This method has many advantages such as wide application range, good treatment effect, long service life, low cost, and convenient operation and maintenance. It uses waste iron scraps as raw materials and does not need to consume power resources. It has the meaning of "treating waste by waste". At present, iron-carbon micro-electrolytic fillers have been widely used in the treatment of wastewater from printing and dyeing, pesticides / pharmaceuticals, heavy metals, petrochemicals and oil separation, and landfill leachate, and have achieved good results. Regarding the effect of TPFC iron-carbon fillers developed by our company on the treatment of various types of wastewater, you can view the treatment effects of TPFC iron-carbon micro-electrolytic fillers in the treatment of various types of wastewater.
Ozone is a strong oxidant. It reacts quickly with reduced pollutants, is easy to use, and does not produce secondary pollution. It can be used for disinfection, decolorization, deodorization, removal of organic matter, and reduction of COD. The use of ozone oxidation method alone is costly and expensive to treat, and its oxidation reaction is selective. It has a poor oxidation effect on certain halogenated hydrocarbons and pesticides. For this reason, in recent years, related combination technologies have been developed to improve the efficiency of ozone oxidation. Among them, UV / O3, H2O2 / O3, UV / H2O2 / O3 and other combination methods can not only improve the oxidation rate and efficiency, but also can oxidize ozone when acting alone. Difficult to oxidatively degrade organic matter. Due to the low solubility of ozone in water, low ozone production efficiency and high energy consumption, increasing the solubility of ozone in water, increasing the utilization rate of ozone, and developing an efficient and low energy consumption ozone generating device have become the main research directions.
Wet (catalytic) oxidation
The wet (catalytic) oxidation method uses O2 or air as an oxidant (adding a catalyst) under high temperature (150 ~ 350 ¡ã C), high pressure (0.5 ~ 20MPa), and catalyst. The (catalytic) oxidation water is in a dissolved or suspended state. Organic matter or reduced inorganic matter, to achieve the purpose of removing pollutants. The wet air (catalytic) oxidation method can be applied to the treatment of urban sewage sludge and industrial wastewater such as acrylonitrile, coking, printing and dyeing, and pesticide wastewater containing phenol, chlorohydrocarbon, organic phosphorus, and organic sulfur compounds.
Plasma water treatment technology
Low-temperature plasma water treatment technology, including high-pressure pulse discharge plasma water treatment technology and glow discharge plasma water treatment technology, uses discharge to directly generate plasma in aqueous solution, or introduces active particles in gas discharge plasma into water. It can completely oxidize and decompose pollutants in water. Direct pulse discharge in aqueous solution can be operated at normal temperature and pressure. During the entire discharge process, no in-situ catalyst can be added to generate in-situ chemical oxidative species in the aqueous solution to oxidize and degrade organic matter. This technology is economical and effective for the treatment of low-concentration organic matter . In addition, the reactor form using the pulse discharge plasma water treatment technology can be flexibly adjusted, the operation process is simple, and the corresponding maintenance cost is low. Limited by the discharge equipment, the energy utilization efficiency of this process for degrading organics is low, and the application of plasma technology in water treatment is still in the research and development stage.
Organic pollutants in water body irradiated with ultrasonic waves at a frequency of 15 ~ 1000kHz are a physical and chemical process caused by cavitation effects. Ultrasonic waves can not only improve the reaction conditions, speed up the reaction speed and increase the reaction yield, but also enable some difficult chemical reactions to be achieved. It combines the characteristics of various water treatment technologies such as advanced oxidation, incineration, and supercritical oxidation. In addition, it is simple to operate and requires less equipment. It is highly toxic and difficult to degrade organic pollution in wastewater treatment, especially in degrading wastewater. It is of great significance to accelerate the degradation rate of organic pollutants, realize the harmlessness of industrial wastewater pollutants, and avoid the impact of secondary pollution. In recent years, there have been more and more studies on the direct treatment or enhanced treatment of organic wastewater using ultrasonic waves. The content involves degradation mechanisms, kinetics, intermediate products, influencing factors, and system optimization.
Since the 1970s, with the development of large-scale cobalt sources and electron accelerator technology, the problem of radiation sources in radiation technology applications has gradually improved. The use of radiation technology to treat pollutants in wastewater has attracted attention and attention from various countries. Compared with traditional chemical oxidation, using radiation technology to treat pollutants requires no or only a small amount of chemical reagents, does not cause secondary pollution, and has the advantages of high degradation efficiency, fast reaction speed, and thorough degradation of pollutants. Moreover, when ionizing radiation is used in combination with catalytic oxidation methods such as oxygen and ozone, a "synergistic effect" will occur. Therefore, the treatment of pollutants by radiation technology is a clean and sustainable technology, and has been listed by the International Atomic Energy Agency as the main research direction for peaceful use of atomic energy in the 21st century.
Industrial wastewater treatment