【文章內(nèi)容簡(jiǎn)介】 s undergone great changes. Traditional printing and dyeing wastewater treatment methods, such as adsorption, suspension, filtration, coagulation and other features simple, easy to operate and process the advantages of maturity, but such treatment is usually to transfer anic matter from liquid to solid or gas, not only did not plete elimination of anic pollutants and consumption of chemicals and pollution caused by waste accumulation and secondary。 biological methods can only remove the printing and dyeing wastewater BOD, COD, especially for toxic and refractory anics and color out of little effect. Single approach can not meet the current requirements of the development of dyeing wastewater. 2 Printing and Dyeing Wastewater Treatment and Trends traditional methods and process improvement Adsorption Charcoal activated carbon black. Black amorphous granular or fine powder. Activated carbon in the structure due to crystallite carbon is irregular, pores are in cross connection between, on the activation will produce carbon tissue defects, so it is a kind of porous carbon, low bulk density, large specific surface area, do not dissolve in any solvent. A selective adsorption capacities of various gas, anic pigment and nitrogenous base has high capacity of adsorption capacity. Activated carbon has a strong adsorption and chemical adsorption role, can be certain anic pounds adsorption removal effect, making use of this theory, we can quickly and effectively remove harmful substances, the aquarium water odor and pigment and so on, so that the water quality directly and rapidly improve. Activated carbon adsorption is one of the most important the most effective technique of advanced treatment of city sewage, widely used. Activated carbon as an excellent adsorbent has been widely used in water treatment. The best adsorbent is still colored printing and dyeing wastewater. However, activated carbon is expensive, and the regeneration is difficult, so usually only applied to the low concentration of printing and dyeing wastewater treatment and advanced treatment. The biggest problem is difficult to achieve the adsorbent regeneration. At present, domestic and abroad, using activated carbon adsorption method, this method is very effective for the removal of dissolved anic matter in water, but it can39。t remove the dye colloidal and hydrophobic water, and it only cationic dyes, direct dyes, acid dyes, reactive dyes and other watersoluble dye has good adsorption performance. Activated carbon is not the effect on treatment of printing and dyeing wastewater of all types are the same. Activated carbon has selectivity to dyes, the decolorization performance in order of basic dyes, direct dyes, acid dyes and sulfur dyes. Usually activated carbon from animal charcoal, charcoal, carbon to carbon based material through high temperature carbonization and activation. Activated carbon pore, hole, and lack of strong hydrophilic, hydrophobic dye molecules and the limitation of the internal diffusion, applicable to the molecular weight of not more than 400 water soluble dye decolorization, poor decolorization of macromolecules or hydrophobic dyes. Using activated carbon can effectively remove the reactive dyes, basic dyes, wastewater of azo dye. Under certain conditions, activated carbon can also direct adsorption of some heavy metal ions. In addition, carbon adsorption water activity of soluble dye adsorption rate is high, but can not absorb the suspended solids and insoluble dye. Although excellent adsorption performance of activated carbon, but due to the high cost, generally used in low concentration of dye wastewater treatment and advanced treatment. Coagulation Coagulation with low investment costs, equipment, small footprint, processing capacity, decolorization rate and so on. Coagulants are inanic coagulants, anic coagulants and biological coagulant. Traditional coagulation decolorization efficiency on hydrophobic high. It requires change with changes in feed water quality conditions, the decolorization effect of hydrophilic poor, COD removal rate. How to choose an effective coagulation process and efficient coagulant, it is the key to the technology. Chemical Oxidation Study of chemical oxidation is more mature approach. Oxidant monly used Fenton reagent (Fe2, H2O2), ozone, chlorine, sodium hypochlorite, etc.. According to the different oxidants, chemical oxidation can be divided into: ozone oxidation and Fenton39。s reagent oxidation. Ozonation does not produce sludge and secondary pollution, high costs, however, not suitable for large flow waste water treatment, and CODcr removal rate. Seldom a single ozone treatment of dyeing wastewater, but will bine it with other methods, plementary to each other to achieve the best wastewater treatment effects. Wang Xiaojun et