A PARTIAL WETTING MODEL FOR AEROBIC TRICKLING FILTERS

A hydrodynamic description of the partial wetting in an aerobic trickling filter is presented. The wetting efficiency is correlated with the superficial liquid flowrate and to a newly introduced parameter: the minimum peripheral flowrate which characterizes the effective wettability of the packing. It is shown how the latter depends on the packing texture and on the biofilm growth rate. A partial wetting model for trickling filters is developed. By analysing a large variety of experimental data both from the literature and from pilot plant investigations, a relationship is proposed between the minimum peripheral flowrate and the substrate degradation rate, i.e. the biomass activity. The model is compared with empirical correlations reported in the literature and gives physical meaning to the empirical exponents appearing in the various correlations.