Biotrickling FiltersThe main differences between conventional biofilters and biotrickling filters, is that in the later, the aqueous phase is continuously trickled over the packing and the bed is always made of inert materials,. A schematic of the biotrickling filter is shown in Fig. 9.9. Biotrickling filters are more complex than biofilters, yet they have been used in field situations to remove hydrogen sulfide from biogas. This is due to its better performance in handling acidic compounds like hydrogen sulfide, and its easiness in controlling the different physico-chemical operational parameters, viz., pH, temperature and others.