Companies from different industrial sectors regularly use biological aerated filters to reduce pollutants resulting from industrial productions. These filters use a bed of inert material for the growth of a microbial colony which has the key role to break down pollutants. The inert bed is usually formed by organic or inorganic material and always more often from natural products such as the commercial Biodagene which is the product of fired shales from France. This research aims to use clayey Italian rock formations for the production of lightweight expanded aggregates and to test physical -mechanical features of fired products, to verify the possibility of manufacturing a viable alternative media to inert products currently traded.