This presentation presents a framework for selecting optimum alum coagulation conditions for removing Cryptosporidium by conventional water treatment plants. The traditional conventional plant of coagulation-flocculation-sedimentation-filtration is addressed as well as the dissolved air flotation (DAF) plant. An integrated approach is used and thus the presentation deals with the following: fundamental aluminum chemistry associated with alum coagulation including dissolved Al reactions, Al precipitation reactions, and the effect of water temperature; size, number concentration, and the electrical charge of oocysts; bench-scale studies; and, pilot plant studies demonstrating the performance of clarification and dual media filtration for removing Cryptosporidium under optimum alum coagulation conditions. Includes 4 references, tables, figures.