Biogas plant upgrading by adsorption of hydrogen sulfide on treated sewage–sludge was techno-economically assessed. Three different processes were included in the study: the desulfurization of biogas by adsorption, the in-situ regeneration of the adsorbent and its production from sewage-sludge. Biogas plant upgrading was performed for a flow rate of 1000Nm3/h of biogas with a H2S concentration of 2000ppmv and a breakthrough concentration of 200ppmv, which is the technical limit value for internal combustion engines. The cost due to the steam required for the in-situ regeneration was evaluated in two different scenarios: as a bought external utility and as an in-situ produced utility, installing an electric or a biogas steam boiler. According to the cash flow analysis carried out, all the options require a similar minimum selling price for the upgraded biogas (about 0.27–0.29€/Nm3), with a cost of the overall desulfurization process between 2.5 and 4.0c€/Nm3.