Effect of pulp mill chemicals on flocculation in river water

Thousands of pulp mill chemicals have been released into the aquatic environment. Some of them may cause flocculation and deposition of an organic matrix and incoming suspended sediments downstream of pulp mills in rivers, and may have adverse impacts on aquatic ecosystems. Therefore, it is important to identify the chemicals inducing coagulation and flocculation in river water. This assists in understanding the mechanism for its formation, and will improve the transport models by including the effect of flocculation. Presented is the effect of pulp mill effluent related cationic ions and organic polymers on flocculation in river water. The experimental results show that Na⁺, Ca²⁺, fibers, hydrolytic lignin, protein, sucrose, cellulose and starch can induce flocculation in river water.