Non-steady state simulation of BOM removal in drinking water biofilters: Model development

A numerical model was developed to simulate the non-steady-state behavior o f biologically-active filters used for drinking water treatment. The biofil ter simulation model called "BIOFILT" simulates the substrate (biodegradabl e organic matter or BOM) and biomass (both attached and suspended) profiles in a biofilter as a function of time. One of the innovative features of BI OFILT compared to previous biofilm models is the ability to simulate the ef fects of a sudden loss in attached biomass or biofilm due to filter backwas h on substrate removal performance. A sensitivity analysis of the model inp ut parameters indicated that the model simulations were most sensitive to t he values of parameters that controlled substrate degradation and biofilm g rowth and accumulation including the substrate diffusion coefficient, the m aximum rate of substrate degradation, the microbial yield coefficient. and a dimensionless shear loss coefficient. Variation of the hydraulic loading rate or other parameters that controlled the deposition of biomass via filt ration did not significantly impact the simulation results. (C) 2000 Elsevi er Science Ltd. All rights reserved.