Processes governing primary biofilm formation.

Biofilm accumulation under turbulent flow condition on the surface of a circular tube is the net result of several process including the following: (1) transport and firm adhesion of soluble components and microbial cell to the surface; (2) metabolic conversions within the biofilm in cluding growth and maintenance decay process; (3) detachment of portions of the biofilm and reentrainment in the bulk fluid. Experiments in tabular reactor were designed to measure the rates of these process during the early stages of biofilm accumulation as a function of the Reynolds number and suspended biomass concentration. Results indicate deposition (i.e., combined transport and adsorption) is only important in the very early stages of biofilm accumulation and is significantly influenced by negligible for the thin biofilms encountered in these experiments. Net biofilm production rates in all experiments decrease to same level and this level is not affected by changes in Reynolds number or suspended biomass concentration. Biofilm detachment rate increases continuously with biofilm accumulation and with increasing Reynolds number.