Electrocoagulation Treatment of Chemithermomechanical Pulp (CTMP) Chemical Pretreatment Effluent

Abstract-Chemithermomechanical pulping becomes an important development direction for pulp and papermaking industry. But the treatment of its effluent is very difficult because of its high concentration of organic pollutants and the deep color. In this study, eucalyptus chemithermomechanical pulp (CTMP) chemical pretreatment effluent was treated with electrocoagulation, and its treatment efficiency was compared with the traditional chemical coagulation. Results showed that under the conditions of 7.5v cell voltage or 4.43mA/cm2 current density, effluent pH of 6, 25 min treatment time, and 1.0g NaCl addition, COD_cr and color removal rates in electrocoagulation treatment reached 40.8% and 90.1% respectively, which were much higher than those of the aluminium chloride and ferric chloride treatment. Based on these results, it is expected that electrocoagulation is a more effective method than chemical coagulation to remove the pollution materials existed in the CTMP chemical pretreatment effluent examined in this study.