This work studies the complete use of untreated and chemically treated olive stone: first, it is applied as biosorbent of lead and later, reused as fuel in a pyrolysis process. The waste was chemically treated with three chemical agents to increase its biosorption capacity. Results from characterization show that the treatment of the OS has sound effects (higher surface area, lower carbon content, lower ashes content, higher calorific value, etc.). These results have important implications on the potential for a productive reuse of these waste materials, since their properties (as biosorbent and as fuel) improve significantly. For the complete use of the waste, the best chemically treated olive stone was chosen to analyze the biosorption-desorption cycles to remove lead from wastewater, obtaining a life factor of nine cycles. After the last cycle, its behavior on pyrolysis process was studied by dynamic thermogravimetry and derivate thermogravimetry. Results show that the thermal decomposition in an inert atmosphere can be modeled by separate decomposition of each of the three fractions which constitute the material. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.