AbstractThe foam separation technique of microflotation was studied usingA. aerogenesas the test organisms. Gas flow rate, collector and alum (when used) concentrations, and frother dose were held constant. In contrast toE. coli, previously reported,A. aerogenesare removed using both lauric acid and laurylamine as the collectors without prior coagulation with alum. The removals are improved after coagulation, with laurylamine being the more efficient collector. In all cases the removals decrease upon increasing the pH above about 8.