content down to less than 1000 ppmv, followed by a biogas deep
cleaning step to reduce its concentration to less than 0.5 ppmv. In
fact, examples of similar cascade biogas treatment units at industrial fuel cell facilities proved to be successful in reaching the fuel
cell specifications [6,14,19]. In particular, this plant consisted of a
biotrickling filter (BTF), adsorption on iron oxides, biogas drying
and adsorption on activated carbon.