AWWA JAW28464

One of the primary objectives of the research described here was to identify the best available measure of the intensity of turbulence with a view to correcting the mixing intensity of the flocculation process to compensate for temperature effects. It was concluded, however, that no one measure of turbulence intensity is better than another. The authors observed that flocculation efficiency at 20C is not sensitive to impeller geometry, but at 5C impeller geometry is much more important. A turbine impeller caused much more floc breakup than a stake and stator impeller. With metal coagulants, the use of constant pOH is appropriate for correcting system chemistry for temperature effects. Alum floc was significantly weaker than iron floc under all conditions tested. Includes 73 references, tables, figures.