The Increasing Interest of ANAMMOX Research in China: Bacteria, Process Development, and Application

Figure 5

Structures of ANAMMOX granules DMP ((b), (m)-(n)), SEM ((a), (c), (e)–(h), (k), and (l)), and TEM ((d), (f), and (i)-(j)). (a) One ANAMMOX granule composed of subunits (marked with closed curve) and ditches (indicated with arrows) separating the subunits. (b) An ANAMMOX granule (on the top left corner) broken into several subunits. (c) Microbial cell clusters (marked with closed curve) connected by the filamentous bacteria and (d) separated by filamentous bacteria-EPS bands (indicated with rectangles). (e) Interstitial space: the honeycomb-like structures (indicated with circles). (f) ANAMMOX bacteria-like cells (marked with a circle). (g) Ditches (indicated with yellow arrows) between subunits in the exterior of granules. (h) Interstitial voids (indicated with yellow arrows) between microbial cell clusters in the exterior of granules and (i) in the interior of granules (indicated with rectangles). (j) Gas tunnels between microbial cells (indicated with arrows). (k) Small gas pocket (marked with rectangle). (l) Gas pocket of a settling granule formed by inflation of dinitrogen gas. (m) Gas pocket of a floating granule (indicated with closed curve). (n) A broken floating ANAMMOX granule formed by the burst of dinitrogen gas [92].