Growth Process of Periphytic Biofilm under Defined Local Hydrodynamic Conditions

Flume experiments were conducted to assess the impact of defined local hydrodynamic conditions on the growth process of periphytic biofilm. Biofilms were developed in four different local hydrodynamics with friction velocities of 0.0027, 0.0064, 0.0117 and 0.0172 m/s respectively over a 36-day period. The initial colonization of microbial community was significantly delayed by high flow velocities. The dry mass, bacterial abundance and total EPS content of biofilms reached their maximal values at a critical friction velocity of 0.0064 m/s, as a result of the conflicting effects of mass transport and shear stress from local flow fluid. The results indicated that local hydrodynamics during periphytic biofilm growth conditioned the structure and composition of biofilms.