The use of polyacrylamides (PAMs) for removing natural organic matter (NOM) from Paraíba do Sul River (Brazil)

This work assesses the efficiency of polyacrylamides for natural organic matter (NOM) removal from Paraíba do Sul River (Brazil) raw water for drinking purposes. Jar tests were performed following an experimental design protocol. Three kinds of polyacrylamides (anionic, cationic, and non-ionic) at 0.2 mg L⁻¹ were tested. After coagulation, turbidity, DOC, UVA₂₅₄ and SCAN (UV-absorbing material) were determined. Color and pH were also measured. It was found that polyacrylamides did not reduce the amounts of alum and lime needed in the process and that the amount of alum alone for removing UV-absorbing organic matter is significantly higher. Efficiency of the coagulation process decreased as follows: non-ionic → cationic → anionic → no polyacrylamide. Removal efficiencies for the best case were: 100%, 90%, 83%, and 68% for turbidity, DOC, UVA₂₅₄, and SCAN, respectively.