As the sewage of chemical plant with heavy polluting waste water, it has high chroma, high content of pollutants in sewage, many biological refractory substances, many toxic and harmful substances, complex water quality components and many by-products. These characteristics not only lead to the wastewater treatment of chemical plants Difficult, and the environmental hazards, this article briefly introduces the five major chemical plant sewage treatment process, see below.
Chemical treatment
Chemical method is the use of the role of chemical reactions to remove water, organic matter, inorganic impurities. The main chemical coagulation, chemical oxidation, electrochemical oxidation and so on. Chemical coagulation is the main object of the role of small suspended solids and colloidal substances in water, through the addition of chemical agents produced by the cohesion and flocculation, the colloidal destabilization of precipitation and removal. The coagulation method not only can remove small suspended particles with particle size of 1O ~ 10mm in wastewater, but also can remove chrominance, microorganism and organic matter. The method is greatly affected by the change of pH value, water temperature, water quality and water quantity, and has low removal rate for some organic and inorganic substances with good solubility. The chemical oxidation method is usually a method of oxidatively removing organic pollutants from chemical wastewater by an oxidant . Wastewater through chemical oxidation and reduction, the wastewater can contain organic and inorganic toxic substances into non-toxic or less toxic substances, so as to achieve the purpose of wastewater purification. Commonly used in air oxidation, chlorine oxidation and ozonization. Air oxidation due to its weak oxidizing power, mainly for the treatment of wastewater containing more reductive substances, Cl is a commonly used oxidant, mainly used in the treatment of organic wastewater containing phenol, cyanide, ozone wastewater treatment, oxidation Strong, no secondary pollution. Ozone oxidation, chlorine oxidation, the water treatment effect is good, but the energy consumption, high cost, not suitable for dealing with large amount of water and the concentration of relatively low concentration of chemical wastewater; electrochemical oxidation method is in the cell, the organic pollutants in wastewater In the electrode due to the oxidation and reduction reaction to remove the pollutants in the wastewater electrolysis cell anode loss of electrons are oxidized, the water of Cl-, OH-, etc. can also be discharged at the anode to generate Cl2 and oxygen and indirectly oxidative destruction of pollution Things. In fact, in order to strengthen the oxidation of the anode and reduce the internal resistance of the electrolyzer, some sodium chloride is often added to the wastewater electrolyzer for the so-called electrochlorination. Chlorine and hypochlorite are generated in the anode after the addition of NaCl, On the water of inorganic and organic matter also has a strong oxidation. In recent years, some new electrode materials have been found in electrooxidation and electroreduction. Some achievements have been made, but there are still some problems such as high energy consumption, high cost and side reactions.
2 physical treatment method
The common physical methods of chemical wastewater include filtration, gravity precipitation and flotation. Filtration method is to retain the pore granular granular layer of water interception of impurities, mainly to reduce suspended solids in the sewage in the chemical treatment, the commonly used wrench filter and microporous filter, microporous tube made of polyethylene, Pore ​​size can be adjusted, more convenient exchange; Gravity precipitation method is the use of suspended particles in water sedimentation performance, the role of gravity in the natural sedimentation role in order to achieve a solid-liquid separation process; flotation method is generated by adsorption Small bubbles wrapped around carrying suspended particles out of the way. These three physical methods have simple process and convenient management, but can not be applied to the removal of soluble wastewater, which has great limitations.
3. Photocatalytic oxidation technology
Photocatalytic oxidation technology uses photo-induced oxidation of O2, H2O2 and other oxidants combined with optical radiation. The main light used for UV light, including uv-H2O2, uv-O2 and other processes can be used for sewage treatment CHCl3, CCl4, PCBs and other refractory substances. In addition, in the Feton system with UV light, there is a synergistic effect between UV light and iron ions, which greatly accelerates the rate of hydrogen peroxide decomposition to generate hydroxyl radicals and promotes the oxidative removal of organic compounds.
The so-called photochemical reaction, that is, only under the action of light to carry out chemical reactions. The reaction of molecular absorption of light energy is excited to a high energy state, and then electronically excited state molecules for chemical reactions. The activation energy of photochemical reactions is derived from the photon energy. In solar energy utilization, photoelectric conversion and photochemical conversion have been very active in photochemical field. In the early 1980s, photochemical applications of environmental protection began to be studied. Among them, photochemical degradation and pollution control were paid more attention, including photocatalytic degradation without catalyst and catalyst. The former uses ozone and hydrogen peroxide as the oxidant, which oxidizes and decomposes the pollutants under the irradiation of ultraviolet light. The latter is also called photocatalytic degradation and can be generally divided into two types: homogeneous and multiphase. Homogeneous photocatalytic degradation of Fe2 + or Fe3 + and H2O2 as the medium, by photo-Fenton reaction so that pollutants are degraded, such reactions can be directly used by visible light; multi-phase photocatalytic degradation is in the pollution system In the vote plus a certain amount of photosensitive semiconductor materials, combined with a certain amount of energy radiation, the photosensitive semiconductor under the excitation of light to produce electron-hole pairs, adsorbed on the semiconductor dissolved oxygen, water molecules and electron hole interaction, OH and other highly oxidizing free radicals, and then through the hydroxyl and the contaminants between the hydroxyl, substitution, electron transfer so that all or nearly all of the contaminated mineralization, the final generation of CO2, H2O and other ions such as NO3- , PO43-, S042-, Cl- and the like. Compared with the photocatalytic degradation without catalyst, the application of photocatalytic degradation in the treatment of environmental pollution is more active.
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Special designed axial-flow type air blower applies belt reduction gear,reducing low noise and sufficient wind; tailor-made water-drop noise
reduction carpet to eliminate water sound.
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Wuxi Ark Fluid Science Technology Co., Ltd. , https://www.fangzhouarkfluid.com