Author(s)

H. Horn

Abstract

A biofilm model for small streams is presented. RlOVAL has been developed for the simulation of self-purification in small running waters. In these streams with volumetric flow rates less than 0.5 mVs, the self-purification processes take place in the benthic biofilm. The developed stream model treats the stream as a plug flow reactor. The self-purification in the stream is based on a steady state biofilm model. The composition of the biofilm with autotrophic and heterotrophic biomass did not change with time or space. The model took account of the oxygen concentration, the ammonia concentration, the biochemical oxygen demand and the temperature in the water body and in the biofilm. The bottom structure of the stream determines the surface area for the biofilm and, with it, the self-purification

Keywords