RAPID BIOFILM DEVELOPMENT IN DEEP GROUND WATER BY GALLIONELLA FERRUGINEA
The development of Gallionella ferruginea biofilms and the associated iron precipitation in flowing ground water from two 46 m deep wells were studied over 48 h. The bacterium formed biofilms of up to 1.76 /ìg total organic carbon per cm2 with 18.8 /ìg precipitated iron per cm2. Microscopic observations revealed multilayered net-works of the bacterium mixed with iron precipitates. Intermittent turbulence decreased the biofilm development by a factor of three. The experimental set-up proved to be a useful tool for determination of potential clogging problems and showed that G. ferruginea may constitute an important problem in the development of ground water heat pump technology.