Accumulation and control of biomass in biotrickling filters for waste gas purification

Packed columns for waste gas treatment may clog at higher carbon loading rates due to excessive biomass accumulation upon their packing material. In this paper the mass accumulation data from literature have been collected that were obtained by weighing of a trickling filter during operation. The implications of the observed behaviour for design and modelling are discussed. Parameters are introduced to quantify and describe the clogging process: a characteristic clogging time tau(clog) and the Carbon Conversion per unit void packing Volume per unit of time (CCV). Methods proposed in literature to eliminate clogging problems are summarised and evaluated. Compression of cloth type packing materials is introduced as a promising biomass control strategy. Measurements in a laboratory set-up show that this approach allows the application of packing materials with a high specific surface while the risk of clogging of the filter bed is eliminated.