Application of Chemical Coagulation Method for Paper-Recycling Wastewater Treatment

Paper-recycling wastewaters have high volume and high pollution and its treatment is the most difficult and complicated process because of their colored pollutants and certain rigid chemical structure. In this study, the efficiency of alum in coupled with polyaluminum chloride (PACl) coagulant on the treatment of paper recycling wastewater was investigated. The effects of initial pH, initial COD and coagulation concentration on sludge volume index (SVI), and turbidity and COD removal were studied. Set tested for coagulation process was 2-12 initial pH, 200-2000 mg/l of alum concentration, 50-1500 mg/l of PACl concentration and 250- 2250 mg/l initial COD. According to the data obtained from batch studies, maximum percentage removal of turbidity and COD 89.90% and 85.16% respectively. The SVI of 193 ml/gr was found in this study. This study showed that the alum and PACl coagulants have high ability to remove pollutants from wastewater factory.