Flocculation of Esch. coli with cationic polymers: a model for the dose curve based on charge

Continuously grown cells from a glucose limited chemostat were flocculated with four different cationic polymers. The polymer was added to the cells either dropwise or as a slug at the start of the flocculation period. Dose curves for each polymer type and using each method of polymer addition were constructed. It was evident that classical overdose was possible with all four polymers if slug addition was used. Continuous addition produced dose curves overdose was possible with all four polymers if slug addition was used. Continuous addition produced dose curves with no overdosing except when low molecular weight, low charge density polymer was used. The dose curves could be combined if they were based on amount of charge added. The dose curve was not linear, but fitted a logarithmic model well. Charge density was much more important than MW of the polymer.