Biotrickling Filters Biotrickling filters Biological treatment system Utilizes a plastic media with large specific surface for the stablishment of a biofilm and increasing gas-liquid transfer Smaller footprint than biofilters due to its design with shorter contact times and greater bed height Requires water supply with nutrients (normally filtered secondary effluent, or chlorine-free tertiary effluent) Continuous operation regime Sectors: urban and industrial wastewater treatment plants