Removal Of Particular Pollutants In Printing And Dyeing Wastewater By Adsorption-Catalytic Ozonation

Zhejiang province is among one of the provinces which has the most printing and dyeing companies. The wastewater from the companies is100～200tons per ton of textile and80%～90%of the wastewater have been discharged into ecological system. The discharge of printing and dyeing wastewater is of a great volume, with its complex composition including many non-biodegradable organic matters. With the stricter national standard of the water quality, the conventional treatment of the printing and dyeing wastewater, like Aerobic Bioremediation, can meet the requirement of the advanced treatment of the wastewater.Organic matters in printing and dyeing wastewater were analyzed by GC-MS, HPLC. Results shows that printing and dyeing wastewater has a complex composition,2-chloro-2-methyl-butane, chloroform and acetophenone are chosen as particular pollutant. Because of the accumulation in treatment process, the acetophenone’s relative amount increases in primary clarify, secondary clarify, and final clarify, and the relative percentage of acetophenone reaches24.5%in final sedimentation tank, which is the highest among all organic pollutants. Therefore, acetophenone is chosen as the target particular pollutant for experiment.The degradation of acetophenone by adsorption-catalytic ozonation was studied, and the effect of ozone gas flow, GAC dosage, pH value on the adsorption-catalytic ozonation was researched as well as the cooperation factor and mechanism in adsorption-catalytic ozonation system. A generalized kinetic model was proposed to describe the treatment process. Furthermore, carbon was made from water hyacinth in test, and the effect of water-hyacinth-based carbon on adsorption-catalytic ozonation was also examined under the optimum conditions.The results shows that the increase of ozone inlet fluxes, GAC dosage, and pH benefit the removal of acetophenone by adsorption-catalytic ozonation. The optimum condition for acetophenone degradation is50mg L-1in ozone inlet flux,200mg L-1in GAC dosage, and10.0in pH value, and the acetophenone removal rate can reach92.3%in20minutes at this condition. The best synergy can be obtained when the pH value is10.0, and the removal rate of acetophenone by ozonation and GAC adsorption alone can be enhanced by37.6%and63.2%compared with adsorption-catalytic ozonation respectively. The active carbon acts as a catalyst in the adsorption-catalytic ozonation system. And the performance of the carbon from water hyacinth is not as good as commercial carbon.