Characteristics of biofilm development in an operating rainwater storage tank

For better understanding of the environmental conditions in rainwater tanks and the development of biofilms therein, the physicochemical and microbial conditions were investigated and compared along with the changes in biofilm cells and the bacterial community during biofilm development in the inlet and outlet of a rainwater tank. Differences were observed in some of the physicochemical and microbial parameters between the inlet and the outlet, and the bacterial composition differed at each stage of biofilm development with the bacterial community structure exhibiting greater evenness as the biofilm matured. It was confirmed that the biofilm development process takes place in four stages: an initial stage characterized by the colonization of different populations, an intermediate stage characterized by a limited number of dominant populations, a late/mature stage characterized by mature biofilms of a complex spatial structure, and a detachment stage. It was concluded that the nutrient and microbial parameters differed by location within the rainwater tank because of its baffle and inlet barrier design, which also appeared to have an influence on the bacterial composition and biofilm development rate.