In order to establish the role of biofilm in rainwater tank, it was investigated the phylogenetic distribution of the bacteria present in an operating rainwater tank. Most of the bacteria were closely related to fresh water, soil, and biofilm bacteria found in natural environments. The high proportion of proteobacteria indicates the generally clean oligotrophic nature of the tank water. To better understand the environmental conditions in rainwater tanks and the development of biofilms therein, the changes in biofilm cells and the bacterial community were investigated during biofilm development. We confirmed that the biofilm development process takes place in three stages: an initial stage characterized by the colonization of different populations, an intermediate stage characterized by a limited number of dominant populations utilizing similar resources, and a late/mature stage characterized by mature biofilms of a complex spatial structure. It was investigated microbial behaviour after inoculation of the bacterium, Pseudomonas aeruginosa, in pilot and full-scale rainwater tanks with different surface-to-volume (S/V) ratios. Ninety-nine percentage of the inoculated P. aeruginosa had been removed from the water phase. The faster removal rate in pilot and full-scale tank was due to its higher S/V ratio. From the results, several recommendations for tank design and management were suggested.
Part of the book: Microbial Biofilms