A Gram-negative, aerobic, non-motile, rod-shaped, floc-forming, and non-spore-forming bacterium, designated as NLF-7-7(T), was isolated from the biofilm of a sample collected from a livestock wastewater treatment plant in Nonsan, Republic of Korea. Strain NLF-7-7(T), forms a visible floc and grows in the flocculated state. Cells of strain NLF-7-7(T) grew optimally at pH 6.5 and 30 degrees C and in the presence of 0.5% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NLF-7-7(T) belonged to the family Comamonadaceae, and was most closely related to Comamonas badia DSM 17552(T) (95.8% similarity) and Comamonas nitrativorans 23310(T) (94.0% similarity). The phylogenetic and phenotypic data indicate strain NLF-7-7(T) is clearly distinguished from the Comamonas lineage. The major cellular fatty acids were C-10:0 3OH, C-16:0, and summed feature 3 (C-16:1 omega 6c/C-16:1 omega 7c). The respiratory quinone was Q-8. The polar lipids were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. The DNA G+C content of strain NLF-7-7 was 68.0 mol%. Based on the phenotypic, chemotaxonomic, and phylogenetic properties, strain NLF-7-7(T) represents a novel species of the genus Comamonas, for which the name Comamonas flocculans sp. nov. is proposed. The type strain is C. flocculans NLF-7-7(T) (=KCTC 62943(T)). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Comamonas flocculans NLF-7-7(T) is MN527436. The whole-genome shotgun BioProject Number is PRJNA555370 with the Accession Number CP042344.