Experimental Research On Advance Treatment Of Printing Wastewater By Ozone-UV And Fenton Reagent

Because of its large amount and high pollutants concentration, the printing wastewater has already become one main industrial pollution source which threaten water environment seriously. As the Chinese national standards on effluent are on the way of increasingly strictness, the trend for advanced treatments and recycling on this kind of water is irresistible. In this thesis, two methods, UV—ozone peroxide solution and Fenton, are adopted for advanced treatment on printing wastewater; the influence and effects of ozone oxidation and UV—ozone process on the removal effectiveness of wastewater COD and the removal of color are studied; the principles and influencing factors of Fenton reagent oxidation are researched; the optimum operational parameters are determined through the single factors influence test.In this research, the ozone oxidation process of pulping is applied in the treatment of printing wastewater. The experiment results show that, on the best experiment conditions when pH is 9, h/d is 12, ozone producing gas rate is 8g/h, the removal rate of COD arrives to 52.87% when the ozone dosing quantity is 160mg/L; under the same condition, when the ozone dosing quantity is 180mg/L, the chrome removal rate rise to 98.1%. When the UV—ozone process and oxidation process are combined, and on the best experiment conditions that pH is 9, h/d is 12, the ozone producing gas rate is 8g/h, the ozone dosing quantity is 160mg/L, the UV is 40 W, the removal rate of COD is 64.1%, the concentration degree of COD drops from 220mg/L to 79.2mg/L; under the same conditions, when the ozone dosing quantity is 180mg/L, the chrome removal rate reached 99.6%, and the chrome is almost 1, which meet the sewage reuse criteria.In this paper, the Fenton is applied in the printing wastewater process and the optimal operating conditions are determined with the help of orthogonal experiments and single-factor analysis:the mole ratio of [H2O2]/[Fe2+] is 10:1, the addition amount of FeSO4·7H2O is 0.75mmol/L, pH value of incoming water is 5.0, reaction time is 120 minutes. The removal rate of COD reachs to71% and the chroma removal rate reachs to 97%.The results of experiment suggest that the UV/O3 and coagulating sedimentation process is effective in treating the pulp and printing wastewater. Eventually, the COD in wastewater will deeply fall from 220mg/L to 80mg/L, chrome almost drops from 100 times to 0; the Fenton oxidation process is very useful in reducing COD from 220mg/L to 65mg/L, the chrome declines from 100 times to 3 times, all of which could achieve the Chinese national sewage reuse criteria.This article is a great exploration on new methods in processing the printing wastewater. Through a series of tests, it has been proved that the parameters are in good running, and the effect of experiment is significance. Studies in these research is meaningful in printing wastewater treatment.