MICROBIOLOGY OF SCUM FORMED AT THE SURFACE OF LAGOONED WASTEWATER.

Laboratory experiments were conducted to study the microbiology of the viscous scum. The scum, which formed within 2 days of start-up, was composed of many different zoogloeae, threadlike bacteria, spirilla, egg-shaped cocci, cocci, cocco-bacilli, and bacilli. Bacterial isolates made from the scum differed greatly from those made from raw wastewater but resembled those made from activated sludge by other investigators. Four main groups of zoogloeae were identified.