“…Currently, in Mexico, different natural supports are used for bacterial growth and in wastewater treatment, such as tezontle, charcoal, pumice, river sand, tepetate, perlite, zeolites, and vermiculite. Sepiolite has been used as a support medium for microbial adherence in different wastewater treatments in Spain, with good results (Arnaiz et al, 2006;Diez et al, 1995;Martin et al, 2008). For example, immobilized microorganisms are used for the decontamination of wastewater in treatment plants of fixed biofilm, with systems such as trickling filters, rotating biological contactors, or fluidized beds (Costerton et al, 1995;Garbi et al, 2006;Nicolella et al, 2000).…”