Abstract
Denitrification caused by attached biomass on a river bed was investigated using mass balance model which incorporated mass transfer on the surface, diffusion and bacterial growth in the biofilm. The biofilm was divided into two layers, aerobic and anaerobic, and denitrification took place in the anaerobic layer.
From the parameter sensitivity analysis, it became apparent that the diffusion rate and density of the bacteria in the biofilm were controlling factors for denitrification per unit area.
Even in the case when the DO concentration in the flow was 20g·m-3, denitrification can occur in shallow and eutrophic rivers, and the attached biofilm to the river bed has the ability of the denitrification of about 2×10-6g·m-2, s-1.
