Analysis of the Influencing Factors on Advanced Treatment of Pulp and Paper Mill Effluents by Ozonation Process

The ozonation of papermaking effluent water after second grade biological treatment was carried out, the influential factors of ozonation on the CODCr and color removal rate of the wastewater under different conditions, such as the reaction time, temperature, original p H value, and concentration of ozone were investigated. The results indicated that during the ozonation process, the removal rate of CODCr and color would increase along with that the reaction time, concentration of ozone increase; as the temperature increased, the removal of CODCr and color would increased at first and then decreased; during the original p H value increasing, the removal rate of CODCr was continuously increased, while the removal rate of color had been keeping high always, the increasing trend became smooth. The optimal experimental conditions as bellow: reaction time was 15 min, temperature was 30℃, original p H value was 8, concentration of ozone was 25 mg·L-1, at this time the removal rate of CODCr and color could reach to 39.87% and 88.51% respectively.