The aim of the paper is highly relevant in different countries dealing with some experimental results obtained in a membrane pilot plant designed to upgrade biomethane to such a quality level that it is worth injecting into the methane grid where it is widespread over many territories especially in Italy. The process chosen is able to upgrade biomethane for different inlet conditions assessing the efficiency of this technology in the presence of pollutants typical of a biogas from anaerobic digesters fed by animal waste and biowaste. Specifically, the experimental tests with binary mixtures CH4/CO2 in the range of typical composition, are carried out tests in order to evaluate the performance of the membrane in the presence of H2S; moreover the results are compared with a prediction model showing a good agreement between experiments and simulation results in terms of biomethane purity and yield. (C) 2014 Elsevier Ltd. All rights reserved.