Interactions between ozone, AOM, and particles in water treatment

Algogenic organic matter (AOM) was extracted from each of two algae (Scenedesmus and Chlorella) and used as a source of organic matter. The goal of this research was to study the effects of ozone on AOM-coated particles with respect to particle stability in model (synthetic) waters, to determine prevailing mechanism(s), and to quantify the effects of different variables. Particle stability was assessed through electrophoretic mobility measurements while particle aggregation was assessed through use of a collision efficiency factor under fluid shear mixing conditions. Changes in humic content, molecular weight, acidity, and complexation capacity of AOM with calcium was studied before and after ozonation. The results revealed that flocculation benefits from ozonation can be derived only if calcium binding increases significantly after ozonation. The magnitude of the increase in calcium binding is dependent on the type of AOM being studied and its reactivity to ozonation. The results also emphasized the significance of the molecular weight of the AOM in the flocculation process.