The purpose of this report is to present the characteristics of 021N.  021N is one of the few filaments that encompasses a wide range of traits.  These traits include trichome morphology (021N can be straight, smoothly curved, to at times a slightly coiled filament), additional structures (these structures include gonidia, rosettes, sulphur granules, and a holdfast for anchoring), and a wide variety of shapes that define individual cells in the trichome (from rectangles, barrel-shaped, to ovoid). The length of the filament can be as short as 100 µm to as long as 500 µm. An individual cell can vary in width from 1.0-2.0 µm. A heavy cell septa may be present after the cell dies. 021N is Gram negative and Neisser negative. 021N is well known for its ability to create bulking problems due to its nature of extending itself out from the floc and bridging between flocs.