Chemical wastewater generally comes from inorganic chemical and organic chemical wastewater. Generally, chemical wastewater can be divided into petrochemical wastewater, synthetic chemical wastewater, textile printing and dyeing industrial wastewater, pharmaceutical chemical wastewater and coal chemical wastewater. Due to different sources of wastewater, there are also obvious differences in water quality. In general, chemical wastewater contains various artificial compounds, which are obviously polluting and difficult to degrade. Specifically, the characteristics of chemical wastewater include: First, the water quality and quantity are unstable; Second, the composition of water quality is very complex; Third, the BOD and COD contents are high; Fourthly, the pH value fluctuates greatly; Fifth, it is toxic and irritating; Sixthly, it has high chromaticity; Seventh, the content of salt and oil is relatively high.

Chemical wastewater treatment technology and its application progress

Physical Method and Its Application Progress

Physical method refers to a treatment technology that separates the water contained in the suspended solids through mechanical and physical actions. It is usually used to remove the floating objects in the wastewater, as well as the suspended solids, sand, oil, etc. contained in the wastewater. At the present stage, there are mainly three physical and chemical wastewater treatment methods widely used in the chemical industry: one is gravity sedimentation; The second is filtering method; The third is air flotation method. The gravity precipitation method is mainly based on the characteristics that the density of suspended particles in water is greatly different from that of water, relying on the gravity field to make them precipitate, so as to achieve the purpose of solid-liquid separation. The filtering principle is to remove the insoluble impurities contained in the water through the filter layer, usually by means of filters, microporous tubes and other equipment to reduce the suspended solids contained in the water. Air flotation refers to the adhesion of suspended solids in water by means of highly dispersed micro bubbles, and the effective separation of water and suspended solids by means of density difference. This treatment technology is generally applied to the separation of oil and hydrophobic fine suspended solids. The physical method is generally simple in the specific process, but the disadvantage is that it is difficult to separate the soluble components. At present, the physical technologies used in chemical wastewater treatment mainly include magnetic separation technology and membrane separation technology. Among them, some studies have found that the magnetic separation technology can effectively improve the sludge sedimentation during the implementation of the activated sludge method. In specific applications, the magnetic powder needs to be added to the wastewater to give play to its magnetism, so that the magnetized sludge can be successfully adsorbed to achieve effective recovery and application.

Chemical method and its application progress

Chemical method refers to a method that can promote the change of material properties through chemical reaction to achieve effective treatment of colloids and dissolved substances contained in sewage. At present, chemical wastewater treatment methods widely used in the chemical industry mainly include electrochemical oxidation, chemical coagulation and chemical oxidation. Chemical oxidation method is mainly to select ozone, chlorine and other oxidants to add to the wastewater, and effectively oxidize those organic pollutants that are difficult to degrade to achieve effective treatment. It is reported that the application of ozone in the treatment of methyl methacrylate semiconductor wastewater is conducive to promoting the effective improvement of methyl methacrylate removal rate. Electrochemical oxidation is to play its catalytic role in the oxidation reaction through light, sound, electricity and magnetic reagents to achieve effective treatment of chemical wastewater. This method can play a significant role in the application of biodegradable organics.

Physiochemical method and its application progress

Physicochemical method refers to a method that comprehensively analyzes the principle of physicochemistry and combines chemical separation theory to treat wastewater. Generally, physical and chemical methods mainly include ion exchange method, adsorption method, extraction method and separation method. Such wastewater treatment methods can effectively remove fine suspended solids and dissolved organics in wastewater, but they are only applicable to the separation and treatment of certain substances, which is difficult to be applied in a large scale. At the same time, this treatment process is very expensive, and it is likely to cause secondary pollution. The ion exchange method is based on the difference in the affinity of chemical bonds to exchange and reflect the ion exchanger and water ions, so as to achieve effective purification of wastewater. The extraction method is to realize the effective extraction of non-polar organic matters in the wastewater and complete the purification of wastewater by putting extractants into the wastewater and following the similar compatibility principle. Adsorption refers to the use of porous media to adsorb organic pollutants contained in chemical wastewater to achieve the effect of purifying wastewater.