Model development for biotrickling filter treatment of graywater simulant and waste gas. I

A mathematical model was developed to simulate a biotrickling filter capable of simultaneous treatment of graywater simulant and waste gas contaminated with ammonia and hydrogen sulfide. The model accounts for mass transfer of gas phase contaminants into the liquid phase and subsequent transfer into a biofilm where microbial conversions of contaminants are modeled by Monod kinetics. A set of laboratory experiments was conducted to estimate parameters for each of the two components of the model. Separation of parameter estimation both decreased the total number of parameters estimated simultaneously and ensured that each component of the system was adequately represented. Process performance, as predicted by the calibrated model, was compared to results from the operation of bench-scale reactors. The model was capable of accurately predicting contaminant removal and thus was used to make a preliminary assessment on the feasibility of a proposed dual treatment biotrickling filter system. This model is a valuable tool not only to describe and predict process performance, but also to identify relevant design parameters.