Figure 4

Photograph of purple and white S-oxidizing bacteria near the outlet distribution pipe for cells 2 and 3. The purple bacteria are incompletely oxidizing H₂S to elemental sulfur. Similar growths of purple bacteria have been reported for H₂S-rich effluent waters at other constructed wetlands (James Gusek, personal communication, 1999). Although bacterial identification was not attempted in this study, it is likely[78] that the purple microbes include the Chromatiaceae and possibly Rhodospirillaceae, whereas an anonymous reviewer of this article suggested the filamentous white bacteria could be Beggiatoacea.