Anaerobic ammonium oxidation (anammox) bacteria typically form bright red biofilms in waste water treatment plants. This provides them with emergent properties they would otherwise lack as free-living bacteria, including social cooperation (e.g. with ammonium oxidizing bacteria) and tolerance to oxidative stresses, which in turn depend on the structure and functional properties of the exopolymer matrix. In this seminar I will discuss how we sought to extract and identify functionally conserved anammoxexopolymers and then describe their roles in supporting the emergent properties of anammoxbiofilms. This includes facilitating cell-cell adhesion, fundamental matrix structure assembly, and providing oxidative stress tolerance. I will then illustrate how elucidating the role of exopolymers in core anammoxbiofilm functions can inform on strategies to achieve higher N-removal rates by anammox for mainstream and sidestream waste water treatments.