The purpose of this report is to present the physical characteristics of a filamentous bacterium that is present in wastewater. Sphaerotilus natans is a colonial type of bacteria. When the bacteria divide they do not separate and become individual cells that can roam around by themselves. Sphaerotilus natans cells cling to each other and form a filament, thus the term filamentous bacteria. One of the characteristics that is inherent to S natans is that every once in a while the cells branch out from the main filament. This “false branching” can be utilized in the identification of S natans under the microscope. Sphaerotilus natans is a long filament (100-1000 µm) and is usually straight to smoothly curved. The cells are rod-shaped like 1701 but are relatively bigger and better defined. The bacillus-shaped cells vary in size from 0.7-1.0 µm wide to 1.0-2.0 µm long. This filament is Gram negative and Neisser negative and attached growth is rare. Capable of biosorption of Fe, Pb, Cu, Zn, and Cd. Most common granules found within cell is PHB. Fe is oxidized in the sheath. Such iron encrusted sheaths are common in iron rich waters—ferrous iron is normally bound in the matrix of humic and tannic acids.