FORMATION OF BIOFILMS ON SMALL SUSPENDED PARTICLES IN AIRLIFT REACTORS

To overcome the current problems of waste water treatment systems new technologies have to be developed. A promising system is the Biofilm Airlift Suspension-reactor. The aim of these experiments was to determine the effect of dilution rate and acetate loading rate on the early stages of biofilm development in BAS-reactors. During biofilm development bacteria colonize the carrier surface at specific sites in the form of microcolonies which gradually grow out to a full biofilm. Biofilm formation only occurs if the dilution rate is greater than the maximum specific growth rate of the micro-organisms. The yield of biomass on substrate might decrease with decreasing growth rate. More than 95% of the biomass production in the biofilm is transferred by detachment processes to the liquid phase and washed out of the reactor. To elucidate the mechanisms of this detachment processes more experiments are needed.