Hydrodynamic characteristics in biotrickling filters as affected by packing material and hydraulic loading rate

Hydrodynamics in biotrickling filters can be strongly influenced by packing material geometry and hydraulic loading rate. While it is generally accepted that increasing wetted area in a biotrickling filter can improve process performance, additional research on synthetic packing materials and parameters that improve hydrodynamics, resulting in increased wetted area, is desirable. For this research, a series of tracer tests was conducted to compare hydrodynamics in bench scale biotrickling filters with three different packing materials under three different flow rates. Results suggest that of the three packing materials, the material with the highest specific surface area resulted in channeling and excessive formation of stagnant zones within the biotrickling filters. Liquid distribution through the biotrickling filters substantially improved at a hydraulic loading rate of 1.9 mhr for all packing materials, but based on these experiments, improvements were minimal when the hydraulic loading rate was increased further. The presence of a biofilm increased mean residence time in biotrickling filters and the factor by which the increase was observed decreased with increasing hydraulic loading rate.