AWWA WQTC64031

The effect of alum and cationic polymer on dissolved organic nitrogen (DON) removal during alum/polymer coagulation was investigated through bench-scale jar tests. Alum coagulation removed equal or slightly lower amounts of DON as compared to dissolved organic carbon (DOC). At lower alum dosages (< 5 mg per mg DOC), the cationic polymer enhanced DON removal by an additional 15 to 20% over alum alone. At very high alum dosages (> 8 mg per mg DOC), however, the cationic polymer addition negligibly increased DON removal. Results indicated that the DON added as part of the cationic polymer was almost completely removed at optimum alum and polymer doses. Includes 20 references, table, figures.