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Along with continual improvement performance of dye, the resulting difficulty of printing and dyeing wastewater treatment is also increasing.Based on the analysis of printing and dyeing wastewater treatments at home and abroad and color theory, Fenton oxidation-coagulation is discussed on the treatment of printing and dyeing wastewater.In this study, representative water soluble heterocyclic azo dyes, acid yellow23(AY23) based simulation of printing and dyeing wastewater as an object. Firstly, Fenton reagent oxidation treatment, and then treated with coagulation. H2O2dosing quantity, pH value, and the Fe2+ion additive amount, reaction time and reaction temperature on the Fenton oxidation decolorization rate were studied, And explored the mechanism of the influence factors and rulesiOn the basis of single factor on pH value. H2O2dosing quantity, Fe2+ion additive amount were determined by the BBD response surface model, the interaction relations among them and a fixed response surface equation under the condition of reaction time and temperature were built, Meanwhile, with the help of Desingn expert7software, rendered the response surfaces and contour plots.The experimental results showed that, the best decoloring technology optimized by the response surface method:the initial pH of3.19, Fe2+additive amount is23.2mg/L, H2O2dosing quantity is345.4mg/L, the reaction temperature45℃, reaction time5minutes; under the theoretical condition of decoloration rate is90.85%, the differ of it with the actual average decolorization rate of three parallel tests is only2.30%.In the process of coagulation, First of all, made a elaboration on coagulation mechanism, In a summary analysis of the predecessors’research. Analyzed the pH value, reaction temperature. mixing and dosing quantity and species of coagulation，identified the PAC (polyaluminium chloride)+CPAM (cationic polyacrylamide) composite as a coagulant,by single factor experiments,determined optimum value of pH value, reaction temperature, reagent dosing quantity,then on the basis of single factor experiment,orthogonal experiment was proceed.The experimental results showed that, best coagulation condition for processing of AY23 after Fenton oxidation is:Initial pH value is10, respectively CPAM and PAC dosing quantity7mg/L and80mg/L, quick stir2minutes, slow stir20mininutes, temperature35℃. Under the optimum operating conditions, the CODcr degradation is74.8%and decolorization is
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